An enzyme is defined as a
A. a modified protein that lowers the activation energy needed for chemical reactions to occur.
B. a protein that functions as a hormone.
C. a protein that only forms blood.
D. fibrous protein that is used to help build certain tissues in the body.

Option A.

A modified protein that lowers the activation energy needed for chemical reactions to occur.

Explanation:

An enzyme is a protein or biological catalysts that speed up the rate of chemical reactions by lowering the activation energy.

Activation energy is the amount of energy required for a reaction to proceed and over it's barrier.

Enzymes lower the activation energy by binding to one of the reactants called substrate, thereby sticking to it till the energy lowers.

The lower the activation energy, the faster the reaction .

the answer is 1. photosynthesis. glad to

as the gila monster consumes the eggs or young of the desert cottontail and gambel's quail, thus its main food supply is only accessible for a restricted time duration every year. however, for this, the gila monsters exhibit three adaptations, which elevate their survival rate in the desert condition.  

first, is that they possess huge bodies, and can consume greater concentrations of food during a small period. secondly, they require to feed infrequently as they can accumulate fat in their tails. ultimately, their rate of metabolism is very low, so that they can burn their reservoirs of fat gradually.