Hairs are mostly fibrous proteins and are composed of keratin, and also the main constituent of skin, nails, wool, woof, feathers etc.
Keratin is the essential fibrous protein which has a structural and protective functions in the epithelium.
Answer:
Answer is C.
Explanation:
For A and B, a base substitution affects one of the three bases that comprise a codon, the DNA/RNA unit that corresponds to a particular amino acid. If one base is substituted, one codon and therefore one amino acid will be affected. Codons have built-in redundancy, so even by changing one base, the new codon sometimes still corresponds to the same amino acid. Therefore, a base substitution at most affects one amino acid, and sometimes doesn't affect it all.
Frameshift mutations cause a lot more trouble. These occur when you have a deletion or insertion that changes the number of bases in your gene. As a result, the "frame" of the codons changes (everything shifts one way or the other by the number of bases added/removed). This affects EVERY codon downstream of the mutation, so you can imagine that such a mutation would have a bigger effect the closer to the start of the gene it occurs. This is why C is correct.
Answer:
The correct answers would be options 3 and 4.
Natural selection refers to a natural phenomenon by which organisms with survival traits tend to survive and reproduce more as compared to the organisms which lack such traits.
Due to this differential reproduction, survival traits tend to pass on to the offsprings and over several generations the phenotypic frequency of the population changes.
The correct answer is: b. conscious neural control
Neural control of digestive tract is unconscious achieved via the autonomic nervous system.
Local nervous system of the digestive system is called the enteric or intrinsic nervous system. The major components of this nervous system are two networks or plexuses of neurons:
• The myenteric plexus – controls digestive tract motility
• The submucous plexus - regulates gastrointestinal blood flow and controls epithelial cell function.
The right answer is Thanh's grade is 2.5 standard deviations below the mean of the test grades.
The z scores are standard deviations. If, for example, a tool returns a z score of +2.5, it means that the result is a standard deviation of 2.5.
Very high or very low (negative) z scores associated with very low p values are at the ends of the normal distribution.
