Why are stem cells important for the development of a multicellular organism? What do they allow the organism to do?

Stem cells are primal cells found in all multi-cellular organisms. They retain the ability to renew themselves through mitotic cell division and can differentiate into a diverse range of specialized cell types.

Explanation:

In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing specialized cells.

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.