The hard outer covering of an animal is a(n) .

exoskeleton

Explanation:

An exoskeleton is the hard outer covering that supports and protects some animals without backbones.

Hope this helped!!!

the diploid number of chromosomes is sometimes represented by the symbol 2n. for the fruit fly, the diploid number is 8, which can be written as 2n = 8, where n represents twice the number of chromosomes in a sperm or egg cell.

not sure if this what   you'r looking for would be percent composition