What is a gene??
A. A chromosome that determines gender
B. A piece of DNA that controls trait
C. A group of chromosomes
D. A specific form of an allele
(I'm taking a quiz on APEX and I really need an answer ASAP! :))

Option B should be correct.

HOPE IT HELPS...   :)))

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme