The pituitary gland is known as the "master gland" because it is known to control hormones that regulate several other important systems in the endocrine system such as the thyroid gland, ovaries, and testes.
Answer:
Explanation: When the cell increases in size, the volume increases faster than the surface area, because volume is cubed where surface area is squared. When there is more volume and less surface area, diffusion takes longer and is less effective. ... this is actually why cells divide.
Explanation:
Answer:
The options
a. New combinations of genes yielding genotypes of greater fitness
b. Few heterozygotes because of underdominance
c. Frequency-dependent selection, leading to fluctuations in fitness
d. Heterozygotes with greater fitness, owing to overdominance
e. A random assortment of genotypes because of genetic drift
The CORRECT ANSWER IS b.
b. Few heterozygotes because of under dominance
Explanation:
In genetics, underdominance (at times called "negative overdominance") is the opposite of overdominance.
It is the selection against the heterozygote, that leads to disruptive selection and divergent genotypes. It occurs in cases of inferior and reduced fitness (As in our case study, it is the different chromosomal fusions and inversions)
of the heterozygotic genotype to the dominant or recessive homozygotic genotype. It is unstable as it causes fixation of either allele.
Another example is the African butterfly species Pseudacraea eurytus, which makes use of Batesian mimicry to avoid predation. This species carries two alleles that gives a coloration that is alike to a different local butterfly species that is harmful to its predator. The butterflies who are heterozygous for this trait are observed to be intermediate in coloration and thus encounter an higher risk of predation and a decrease in the total fitness.
Correct answer: D
A pollen is where male gametes are produced and so the number of chromosomes, as we are talking about gametes, is n. This means that the grain of pollen will only have a copy of each gene, and therefore only one allele for each gene - one S, and one T or t. So, the possible combinations are ST and St.
