Umm...
biology is the study of life
is this the answer you're looking for?
bam...easy...............
The leaves!
They have chlorophyll to take energy from the sun and use it.
A disturbance that happens repeatedly, as part of a cycle such as the classical economic cycle of boom, bust, revoery, boom, bust, recovery is your answer
<span>the portion of an antigen that binds covalently to an antibody</span>