Cell specialization in multicellular organisms allows cells to

a) reproduce
b) perform different functions
c) respond to their environment
d) be less complex

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.

the answer is sex-linked recessive.