The correct answers are:
Human skin color variation evolved recently in hominid evolution, once some populations of our human ancestors migrated out of Africa.
Human skin color variation is primarily determined by the type and amount of melanin pigment in the skin
Human skin color variation likely evolved in response to differences in the intensity of sunlight around the world.
A skin pigmentation of an individual is under the influence of both:
• Genetics-individual's parents' genetic makeup,
• Environment-exposure to sun.
Human skin color evolved by a process of natural selection in order to regulate the amount of ultraviolet radiation that penetrates the skin.
Pigment responsible for skin color is melanin, produced by skin cell-melanocytes through the process of melanogenesis. Melanogenesis is initiated by exposure to UV radiation, which causes the skin to become darker.
Human skin color variation evolved as our ancestors migrated out of Africa in response to differing sunlight intensity around the world. This variation cannot be attributed to a single gene but is determined by the type and quantity of melanin, involving multiple genes. The range of variability in human skin color is far wider than in our closest primate relatives.
Explanation:Human skin color variation evolved recently in hominid evolution, once some populations of our human ancestors migrated out of Africa. In fact, all humans are believed to have descended from Africa, reflected by the genetic variance found throughout the world. Moreover, skin pigmentation underwent adaptation during the Neolithic era in response to variations in ultraviolet radiation, leading to different skin tones within our species.
However, it is incorrect to state that variability in human skin color can be explained by the activity of a single gene. Human skin color is largely determined by the type and amount of the melanin produced by melanocytes in our skin, and this process involves multiple genes. As for the comparison with our closest primate relatives, the range of human skin color variability is far wider and complex than that observed in primates.
The variation in human skin color likely evolved in response to differences in the intensity of sunlight around the world. Populations living near the equator, where sunlight is most intense, tend to have darker skin which provides a certain level of protection against UV damage. On the other hand, populations living at higher latitudes, where sunlight is less intense, generally have lighter skin, which allows for better Vitamin D synthesis.
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You have to choose between playing a team sport or taking music lessons because the practices overlap. This choice demonstrates that
music lessons are scarce
sports teams are scarce
time is scarce
demand is scarce
The choice demonstrates that time is scarce
Answer: Time is scare.
Explanation:
The time is scare because there is a over lap between the team sport or taking the music lessons. This shows that time is insufficient for the demand.
The time is not sufficient for two of the activities. The time is not available for the music lessons neither the time is available for the team sport.
There is a high demand of time but two things cannot take place at the same time.The demand for time is high but there is nothing one can do for the time, she has to choose from the given two options.
Which of the following traits or characteristics were not found to be more similar in identical twins when compared to fraternal twins in the minnesota twin study?
The traits or characteristics that was NOT found to be more similar in identical twins when compared to fraternal twins in the Minnesota twin study is a.) Tendency to divorce
What was the Twin studies ?
Twin studies are a unique class of epidemiological research intended to quantify the relative contribution of genetics vs environmental factors to a certain trait. The results of older twin studies have frequently been validated by later molecular genetic research, despite the fact that the classical twin studies are still influenced by assumptions developed in the 1920s and that the study design itself is the inherent restriction.
Therefore Tendency to divorce is one of the features or characteristics that the Minnesota twin study did not find to be more similar in identical twins compared to fraternal twins.
complete question;
Which of the following traits or characteristics was NOT found to be more similar in identical twins when compared to fraternal twins in the Minnesota twin study?
a.) Tendency to divorce
b.) Empathy
c.) Intelligence
d.) Leadership
5. Suppose that a dominant allele (P) codes for a polka-dot tail and a recessive allele (p) codes for a solid colored tail. In addition, suppose that a dominant allele (L) codes for long eyelashes and a recessive allele (l) codes for short eyelashes. If two individuals heterozygous for both traits (tail color and eyelash length) mate, what's the probability of the phenotypic combinations of the offspring?
A. 1:1 ratio (half are polka-dot tails and short eyelashes; half are solid tails and long eyelashes)
B. 1:1 ratio (half are polka-dot tails and long eyelashes; half are solid tails and short eyelashes)
C. 9:3:3:1 ratio (9 polka-dot tails and long eyelashes, 3 polka-dot tails and short eyelashes, 3 solid tails and long eyelashes, 1 solid tail and short eyelash)
D. 9:3:3:1 ratio (9 polka-dot tails and short eyelashes, 3 polka-dot tails and long eyelashes, 3 solid tails and short eyelashes, 1 solid tail and long eyelash)
Answer:
C.
Explanation:
According to your problem, you have to two traits to be crossed, tail and eyelashes:
P - polka-dot tail L - long eyelashes
p - solid colored tail l - short eyelashes
It says we cross two individuals that are HETEROzygous for both traits, this means that their genotypes have each allele for each trait. So the cross would be:
PpLl x PpLl
Attached is a Punnet for this cross and ratio count for both genotype and phenotype.
The ratio based on phenotype would be the following:
9 polka-long: 3 polka-short: 3 solid-long: 1 solid-short
The process of photosynthesis can be generally expressed by: carbon dioxide + water glucose + oxygen The process of cellular respiration can be generally expressed by: glucose + oxygen carbon dioxide + water What can be said about these two reactions?
Photosynthesis and cellular respiration are reciprocal processes where the byproduct of one process is the necessary component for the other. Both processes utilize electron transport chains to transfer energy and occur in chloroplasts and mitochondria respectively.
Explanation:The processes of photosynthesis and cellular respiration can essentially be viewed as reciprocal. In photosynthesis, light energy is absorbed to create glucose and oxygen from carbon dioxide and water. This process occurs in chloroplasts. Conversely in cellular respiration glucose and oxygen are metabolized to produce energy, with carbon dioxide and water as byproducts. This process occurs in the cytoplasm and mitochondria. The byproducts of each process become the necessary components for the other process, thus forming an efficient biological cycle. Both processes rely on electron transport chains to capture and transfer the necessary energy for these processes.
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In what year did the US and several other nations agree to reduce the quantity of CFCs used by 50%?
2017
1987
2007
1997
I think 1987 sorry if wrong have a great day
Answer:
1987
Explanation:
The depletion of the ozone layer and the antarctic ozone hole made a danger for the humans to survive on the planet. Depletion of the ozone from the continued use of CFCs can cause skin cancer and many problems which dragged international action to be implemented.
Thus, in 1987, around 56 countries agreed the Montreal Protocol which states the CFC production to cut and also reduction of its use to half.
After few years, this protocol was more strengthened to stop the worldwide production of CFCs and also other chemicals which depletes ozone layer.
What area of the brain experiences rapid growth of synapses and subsequent elimination of those synapses that are not used often during adolescence?
The correct answer is: prefrontal cortex
Synaptogenesis or formation of synapses begins about the 23rd week of gestation. The peak of synapse production is achieved at different periods. The massive overproduction of synapses that occurs in early childhood is followed by a gradual reduction of them also known as "synaptic pruning". “Synaptic pruning” happens during childhood, and during adolescence.
The brain continues to grow and develop, but the overall number of neurons and synapses are reduced by up to 50%. This is process that is experience driven: unnecessary neuronal structures are removed and replaced by more complex and efficient structures, that are more required to the demands of adulthood.
F one species in a community dies out or moves, the community will A) be affected. B) stop working. C) not be affected. D) replace the species
In a community dies out or moves, the community will be affected.
The answer is A. be affected
When there is competition among primates for mates:
a. females may produce more offspring.
b. males may learn to use tools.
c. males may become larger.
d. females may form an all-female residence pattern?
c. males may become larger
A lack of explanation for continental drift prevented many scientists from accepting that a single super-continent called ____ once existed.
A) Glomar
B) Glossopteris
C) Pangaea
D) Wegener
Pangaea is the answer
In humans, free earlobes (E) are dominant to attached earlobes (e) and the presence of freckles (F) is dominant to the absence of freckles (f). If an individual heterozygous for both of these traits were to mate with an individual with attached earlobes and no freckles, what is the probability of having a child with attached earlobes and freckles?
Individual heterozygous for both of these traits has the genotype EeFf while an individual with attached earlobes and no freckles has the genotype eeff (recessive homozygous for both traits). So:
P: EeFf x eeff
F1: (table)
A child with attached earlobes and freckles will have eeFf genotpe from these parents, and the probability is 4/16 or 1/4 (25%).
The probability of having a child with attached earlobes and freckles is 1.
Explanation:In this scenario, an individual heterozygous for both free earlobes (Ee) and the presence of freckles (Ff) is mating with an individual with attached earlobes and no freckles (ee ff).
When they mate, the possible gametes for the heterozygous individual are EF, Ef, eF, and ef. The possible gametes for the other individual are e f.
Therefore, the probability of having a child with attached earlobes and freckles is 1.
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In an active synapse composed of a presynaptic and postsynaptic cell, which part of the presynaptic cell is the last to participate in the action potential? a) Cell body b) Axon terminals c) Axon d) Dendrites e) Axon hillock
Answer:
b) Axon terminals
Explanation:
Dendrite is the receiving part of the presynaptic neuron, while axon is the transmitting part of the neuron. So, after initiation, action potentials travel down axons to the terminals.
Action potential travels through the membrane of the presynaptic cell causing the voltage-gated channels permeable to calcium ions to open. Ca2+ flow through the presynaptic membrane and increase the Ca concentration in the cell which will activate proteins attached to vesicles that contain a neurotransmitter (e.g. acetylcholine). Vesicles fuse with the membrane of the presynaptic cell, thereby release their contents into the synaptic cleft-space between the membranes of the pre- and postsynaptic cells. Neurotransmitter ACh binds to its receptors on the postsynaptic membrane and its binding causes depolarization of the target cell (muscle cell). Depolarization occurs because sodium enters the cell as a result of neurotransmitter receptor binding.
If anna had a child with a man with sickle cell anemia, predict whether that child would also have sickle cell anemia. draw out a pedigree to help explain your reasoning and describe any information you used to make your prediction..
The child has a 100% chance of having Sickle Cell Disease
on the surface of the earth, the force of gravity acting on one kilogram is: _________ newton’s
➷ It would be 9.81 Newtons.
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The duodenal ampulla receives secretions from the
Answer:
The pancreas, liver and gallbladder.
Explanation:
The pancreas, liver and gallbladder all deliver digestive secretions into the duodenum through an orifice known as the ampulla of Vater. This organ is located closely around the middle of the duodenum on the left side.
The duodenal ampulla receives secretions from the bile duct and the main pancreatic duct, which carry bile from the liver and pancreatic juice from the pancreas respectively.
Explanation:The duodenal ampulla, also known as the hepatopancreatic ampulla or ampulla of Vater, receives secretions from the bile duct and the main pancreatic duct. The bile duct carries bile from the liver, while the pancreatic duct carries pancreatic juice from the pancreas. These two ducts join at the ampulla, which opens into the duodenum at a point called the major duodenal papilla. The flow of these secretions is regulated by the hepatopancreatic sphincter, also known as the sphincter of Oddi. Hence, the duodenal ampulla essentially plays a crucial role in the digestive system.
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Which statement most accurately describes what happens to proteins that lack an ER signal sequence?
They are inserted into the ER membrane but do not enter the ER lumen.
They are inserted into the plasma membrane.
They bypass the ER but enter the Golgi apparatus.
They are released into the cytosol.
The correct answer is: They are released into the cytosol.
A a sequence consisting of 5-30 hydrophobic amino acids on the N-terminus, which is called signal peptide or signal sequence is responsible for directing the transport of the synthesized protein. Proteins that contain such sequence are destined for secretion form the cell (vesicular), for the plasma membrane, the lumen or membrane of either the (ER), Golgi or endosomes. So, when the protein lack the sequence, it is released in the cytosol.
An example of effectors' roles in homeostatic responses is observable when an example of effectors' roles in homeostatic responses is observable when an increase in body temperature results from exercise. an increase in body temperature results from fever. a decrease in body temperature results from shock. an increase in body temperature results from involuntary shivering. the rising sun causes an increase in body temperature in a stationary animal.
➷ It would be 'an increase in body temperature results from involuntary shivering.' As you may realize, when you stand in the cold, your body starts to shiver itself. This is from an effector producing a response to try increase your body temperature.
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Effectors are muscles or glands that work to maintain homeostasis through negative feedback mechanisms. They respond to changes in the body's internal state, such as increases or decreases in temperature, by initiating responses to return to a normal state or 'set point'. The mechanisms of homeostasis can be seen in how the body responds to changes in temperature from exercise, fever, shivering, or shock.
Explanation:Effectors play a crucial role in homeostatic responses. These can be muscles that contract or relax, or glands that secrete. For example, when there's an increase in body temperature due to exercise, or a fever, or involuntary shivering, your body responds by initiating cooling mechanisms like sweating. Effectors respond to signals from the brain, usually triggered by sensory input detecting a change from the normal state, or set point. This is a part of a negative feedback mechanism that works to maintain homeostasis, a relatively stable internal state. If our body temperature drops too low, as in the case of shock, the mechanism works the other way, activating effectors that generate heat, such as by shivering, to bring the temperature back up to normal.
Maintaining homeostasis is crucial, as failure to do so can be detrimental and even cause death. There are also positive feedback loops in homeostasis, but these usually move the body further away from homeostasis, such as during childbirth when the levels of the hormone oxytocin increase to facilitate labor.
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Albino trees exist in nature, but they're rare. These trees contain a gene mutation that causes them to lack chlorophyll, so their leaves are white. In California, albino redwood trees are parasites. They survive off the energy from nearby redwood trees. Why do you think they need to use energy from other trees to survive?
Answer:Trees need chlorophyll to make energy. Because albino trees don’t have chlorophyll, they can’t create their own energy. So, they must take energy from other trees to survive.
Explanation:
Cholesterol serves several essential functions in mammalian cells. Which of the following is not influenced by cholesterol?
Select one:
a. membrane permeability
b. membrane fluidity
c. membrane rigidity
d. membrane thickness
The correct answer is: d. membrane thickness
Cholesterol is the second major lipid in the structure of the cell membrane (phospholipids are the major lipid components).
Cholesterol is rigid, so it gives the cell membrane extra support (strength and hardness) by immobilizing some of the lipid molecules around them. This rigidity makes it harder for small molecules to pass through the membrane, so it also has the influence on cell membrane’s permeability (the membrane becomes effective barrier to ions).
Cell membrane’s fluidity is also under the influence of the cholesterol which helps generate some extra space between the lipids allowing them to move freely throughout the membrane.
Which of the following is a function of the protein called ubiquitin?
a.) It attaches to proteins that are marked for destruction in the cell.
b.) It assists in the removal of introns from a eukaryotic pre-mRNA.
c.) It initiates the formation of a transcription complex.
d.) It adds the 3' and 5' caps to eukaryotic pre-mRNA.
The correct answer is: a) It attaches to proteins that are marked for destruction in the cell.
Ubiquitin is a regulatory protein of eukaryotic cell with the various of function. The mechanism of its action involves the addition of ubiquitin to a substrate protein (ubiquitination). Ubiquitin regulatory roles are:
• marking thee proteins for degradation via the proteasome,
• alter the cellular location of proteins,
• promoting or preventing protein interactions.
The protein called ubiquitin functions to mark other proteins for destruction by attaching to them and directing them to the proteasome for degradation.
Explanation:The function of the protein called ubiquitin is to mark other proteins for degradation within the cell. When a protein is tagged with ubiquitin, it is an indication that the protein's lifespan is over, and it should be directed to the proteasome, which is responsible for breaking down and recycling proteins. The process of tagging proteins with ubiquitin and thereby controlling the longevity of these proteins is a key method for regulating gene expression in cells. This post-translational modification is vital for maintaining cellular homeostasis and function.
Answer: a.) It attaches to proteins that are marked for destruction in the cell.
Molecular phylogenies show all land plants are a monophyletic group. This suggests ________.
A) there were many different transitions from aquatic to terrestrial habitats
B) wind-pollinated plants arose first
C) land plants have undergone a diversification since they first colonized terrestrial habitats
D) there was a single transition from aquatic to terrestrial habitats
Answer:
D. There was a single transition from aquatic to terrestrial habitats
Explanation:
Based on the molecular differences at the level of DNA sequence and inheritance, the molecular phylogenies show that all land plants are a monophyletic group. This is why it suggests a single transition from aquatic to terrestrial habitats occur.
Most of a cell function cannot use energy directly from the food we eat . Describe how the energy from the food can be transferred to form later your cells can use?
Energy can be stored in fat cells for later use, there is quick energy(Oranges are a good example for this) and slow energy(fatty foods take longer to break down)
How many copies of DNA does meiosis start with?
Final answer:
Meiosis starts with one diploid cell which has duplicated its DNA, creating two sets of each chromosome. It undergoes two rounds of cell divisions to produce four unique haploid gametes, each with half the original DNA content.
Explanation:
Meiosis begins with one diploid cell that contains two copies of each chromosome, one from each parent. After DNA replication occurs in the S phase of the cell cycle, meiosis proceeds through two cell divisions. The first division, meiosis I, separates homologous chromosomes, each made of two sister chromatids, into two daughter cells. These cells contain a mix of maternal and paternal chromosomes due to random assortment and the crossing over.
During the second meiotic division, or meiosis II, the sister chromatids are separated into four genetically unique haploid cells, each with half the DNA content of the original diploid cell. In humans with 46 chromosomes (23 pairs), the resulting cells from meiosis, which become gametes, each have 23 chromosomes. These are gametes such as sperm in males and oocytes in females.
The variability of the resulting gametes is vast, with the possibility of over eight million (223) different combinations from chromosome alignment alone, excluding additional genetic variation introduced by crossover.
Which of the following statements about transmembrane proteins is correct?They usually have one or more helical regions spanning the membrane bilayer.They are always inserted with the amino terminus on the lumenal side and the carboxyl terminus in the cytosol.They are always inserted with the carboxyl terminus on the lumenal side and the amino terminus in the cytosol.The signal sequences are always cleaved off.They can cross the membrane only once.
The correct answer is: They usually have one or more helical regions spanning the membrane bilayer
Transmembrane proteins are type of integral proteins meaning that they are permanently attached to biological membrane. Transmembrane proteins span through the plasma membrane so most of their structure is hydrophobic.
The major role of these proteins is transport role: they act as a channels that undergo conformational change in order to move a substance through the membrane.
Classified by their structure they can be put into two types: alpha helical and beta barrels.
Transmembrane proteins usually have helical regions spanning the membrane bilayer, their orientation can vary, and they can cross the membrane multiple times.
Explanation:The correct statement about transmembrane proteins is that they usually have one or more helical regions spanning the membrane bilayer. This helical region, also known as a transmembrane domain, allows the protein to cross the lipid bilayer of the cell membrane. While their orientation can vary, transmembrane proteins can have their amino terminus (N-terminus) on either the lumenal side or the cytosolic side of the membrane, and the carboxyl terminus (C-terminus) on the opposite side. Signal sequences in transmembrane proteins are not always cleaved off and can serve various functions. Finally, transmembrane proteins can cross the membrane multiple times, depending on their structure and function.
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How can inheritance be modeled? HELP ASAP!!
using a punnett square or pedigree
What kind of nutrients does the lymphatic system carry to the bloodstream?
The correct answer is: large fats and fat-soluble vitamins
Lymph vessels called lacteals are responsible for the transport of large fats from the digestive tract. Those vessels are located at the beginning of the gastrointestinal tract, predominantly in the small intestine. Fats and fat-soluble vitamins are absorbed from the digestive system and then transported to the venous circulation. The lymph in the lacteals is called chyle.
To what part of the cell do the products of transcription travel
Cytoplasm would be the answer.
The products of transcription, which are mRNA molecules, travel from the nucleus to the cytoplasm of the cell. Here they are translated by ribosomes into proteins. The transportation of mRNA is a key aspect of the central Dogma of Life, covering the flow of genetic information within a biological system.
Explanation:The products of transcription, which are mRNA molecules, travel to the cytoplasm of the cell. In the nucleus, the DNA is transcribed into RNA. Afterwards, the newly synthesized RNA, serving as the intermediate messenger, is transported out of the nucleus and into the cytoplasm where ribosomes translate the RNA into protein. This separation of transcription occurring only within the nucleus, and translation only outside the nucleus in the cytoplasm, is particular to eukaryotic cells.
The transcription process involves the DNA double helix partially unwinding in the region of mRNA synthesis, forming a transcription bubble. It's crucial to note that the mRNA product is complementary to the DNA template strand and that in mRNA, T nucleotides are replaced with U nucleotides.
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Deep-brain stimulation has been reported to provide relief from
Deep-brain stimulation has been reported to provide relief from depression.
Deep brain stimulation (DBS) is a neurosurgical procedure used for the treatment of many diseases such as Parkinson's disease, essential tremor, epilepsy, obsessive–compulsive disorder, dystonia. It includes the placement of a medical device called a neurostimulator which sends electrical impulses, through electrodes, to specific targets in the brain.
It is good method to use for the treatment when disorder cannot be adequately controlled with medications, but it can be risky, e.g. because of the electrode misplacement.
Deep-brain stimulation is a neurosurgical procedure that involves implanting electrodes into specific areas of the brain to treat various neurological disorders. It has been reported to provide relief from conditions such as Parkinson's disease, essential tremor, dystonia, and obsessive-compulsive disorder.
Explanation:Deep-brain stimulation is a neurosurgical procedure that involves implanting electrodes into specific areas of the brain to treat various neurological disorders. The electrodes deliver electrical impulses that help regulate abnormal brain activity and reduce symptoms.
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Which one of these mollusk groups can be classified as suspension feeders?
A) bivalves
B) gastropods
C) chitons
D) cephalopods
The answer is A) bivalves
What processes can change sedimentary rock into metamorphic rock?
A. Subduction and high pressure
B. Erosion and lithification
C. Heating and cooling
D. Uplift and erosion
A) Subduction and high pressure
A. Subduction and high pressure
If you have type A blood, what are your possible genotypes
If you have type A blood then you must have at least one copy of the A allele. However, you could also have two copies of the A allele within type A blood. The genotype, therefore, would be either AO (if they have 1 A allele) or AA (if they have 2 A alleles).