The process by which animals use oxygen to convert food to energy is called

Respiration

Explanation:

Respiration is the process by which animals use O2 to get energy from food. So plants take in CO2 from the air and produce O2, and animals take in O2 from the air and produce CO2

your answer is "the 1950's"

it's     c       this is a cell (b) with a nucleus (c) containing dna (a). the dna is organized into chromosomes (d). a section of the chromosome that codes for a trait is called a gene (e).