Answer:
C. a string of nucleotides that can be used as a template to produce a RNA that codes for a protein.
Explanation:
A gene is a specific sequence of DNA containing genetic information required to make a specific protien and is a string of nucleotides (DNA in cells) that can be used as a template to produce a RNA (by transcription) that codes for a protein. The produced RNA might be the end product (for example some transfer RNA's) or might be further translated into a protein. An organism's entire complement of DNA is its genome.
The first stage of cellular respiration is glycolysis. It does not require oxygen. During glycolysis, one glucose molecule is split into two pyruvate molecules, using 2 ATP while producing 4 ATP and 2 NADH molecules.