The sum of all chemical reactions carried out in an organism is A. metabolism
B. unicellular
C. homeostasis
D. cells

i'd say that the moon rock is about 2.2 billion years old.

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides

answer; aerobic conditions; citric acid cycle (krebs cycle) electron transport chain;         anaerobic conditions; fermentation; both glycolysis;