
The primary source of energy in a food chain is Sun, because producers are the ones that prepare food by themselves and that food is then passed on to higher levels in food chains. And as the producers make their from Sunlight, the primary source of energy in food chain is <u>Sunlight</u> .
An enzyme is a protein molecule in cells which works as a biological catalyst. *brainliest pls*
The original source of all genetic variation is <span>mutation.</span>