Skeletal muscles whose primary function is extension of a joint include the

The answer is triceps muscles. These muscles run along the back of the upper arm while the biceps run along the front. The triceps muscles allow the arm to extend at the joint of the elbow, therefore an antagonist of the biceps that bend the forearm.

g1

choices:

a. g2. b. g1. c. m

cell division has two checkpoints namely, g1

checkpoint and spindle assembly checkpoint. the checkpoint which determines if

division has properly occurred is the g1 checkpoint. at this point, is a damage

in the dna is detected or  the has not reach the optimum size, the cell is

stopped in g1 and is not allowed to proceed to further process.

source:

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.