Coupled reactions are:
a. energetically favorable
b. brings energetically favorable and nonfavorable reactions together
c. needs the of enzymes in order to occur
d. none of these choices seem right
e. i think choices a to e seem to be correct

a. Energetically favorable  

Explanation:

Coupled reactions are exergonic with endergonic reactions, which conserve a great deal of chemical energy from food nutrients in a usable way.

Two reactions can occur simultaneously, such that the energy released in one is stored by the other. These are coupled reactions, such as some that occur in glucose oxidation, whose energy is transferred to ATP. Coupling reactions decreases the amount of energy lost.

answer; ///(b) it is composed of four protein chains and four heme groups;

it is called the mitotic spindle