Mantle
In mollusks with shells, the outer cells of the mantle secrete
calcium carbonate and conchiolin to form the shell. The mantle is the body wall
of a mollusk. It resides below the shell where it covers the body of the
animal.
D. homologous chromosomes pair up
1. Energy from the sun is transferred to earth's surface. Some of that energy is then transferred to the air above the surface.
2. The closer a location is to the equator the more energy it receives from the sun. Therefore a location's air temperature is affected by its distance from the equator.
3. An effect my have more than one cause. These may be linked into a chain of effects and causes.
Answer:
Epistasis
Explanation:
In epistasis, the interaction between genes is inimical, such that one gene masks or interferes with the expression of another. “Epistasis” is a word coined of Greek roots that mean “standing upon.” The alleles that are being masked or silenced are said to be hypostatic to the epistatic alleles that are doing the masking. The cause of the biochemical basis of epistasis is a genetic pathway in which the expression of one gene is dependent on the function of a gene that precedes or follows it in the pathway.
The example of epistasis given is the pigmentation of mice. we were told that "if a mouse has two recessive alleles for coat color, it is always albino no matter what the genotype of other genes involved in coat color"
Let say recessive allele (rr), it is always albino irrespective of other type of other genes, this is true in the stance that epistasis can be reciprocal such that either gene, when present in the dominant (or recessive) form, expresses the same genotype.
