In mammals the digestive tract is made up of multiplesuch as the stomach, pancreas and intestines. These all work together to form the we use to digest food.

Explanation:

In mammals the digestive tract is made up of multiple chambers such as the stomach, pancreas and intestines. These all work together to form the alimentary  we use to digest food.

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).   so the answer is a.