Proteins are macromolecules that are made up of the subunits that are called amino acids, there are 20 fundamental kinds of amino acids present. These varying combinations of them make different proteins needed for numerous functions.
An electron carrier is a molecule that transports electrons during cellular respiration. ... The energy stored in NADH + H+ and FADH2 will be released later in cellular respiration to generate ATP, which can be used as an energy source throughout the cell.
It would be A, because a fossil forms after an animal dies, and hundreds to thousands of years of soil or sediment coversit's body, preserving it. :)
