The somatic nervous system can alter the activities of its targets, the skeletal muscle fibers, because a) it is electrically coupled by gap junctions to the muscles. b) its signals bind to receptor proteins on the muscles. c) its signals reach the muscles via the blood.

B) its signals bind to receptor proteins on the muscles

Explanation:

Somatic nervous system is together with autonomic nervous system part of the peripheral nervous system. Its role is to control the movements of skeletal muscles which means that this nervous system is under the voluntary control (unlike autonomic which is involuntary nervous system). Somatic system consists of two types of nerves:

The axons of the efferent nerves  form a neuromuscular junction with the effector cells, muscle cells.

step 1 ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. this is called nitrification. 2. step 2 the deer eats the plants and uses the nitrogen-containing proteins for cell growth. 3. step 3 bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium. 4. step 4 some of the nitrates are absorbed back into plants, but denitrification breaks down the nitrates into nitrogen gas released back into the atmosphere. 5. step 5 nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification. 6. step 6 plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.