Question

read the paragraph, then choose the word that best completes the sentence.
grabbing a small object, such as an apple, may seem automatic and easy. but few people consider the complex biological mechanism underlying this simple act. neurons in the brain instantly fire in patterns that send commands down the spinal cord. these commands are relayed to muscle tissue in the arm. the tissue contracts, raising the arm, extending an elbow, or flexing the wrist and fingers. for some people with spinal cord injuries, those commands are hindered by their damaged nervous systems. their brains are no longer able to send messages throughout their bodies. for these people, these actions may require substantial effort or be completely impossible.
this process is ________.
a excessive
b unconscious
c unprecedented
d hazardous

Explanation:

The text describes that grabbing an object seems automatic. "Unconscious" means not done with conscious thought, which fits as the process (neurons firing, commands relayed etc.) happens without people consciously thinking about each step. "Excessive" means too much, which doesn't fit. "Unprecedented" means never done before, which is not relevant here. "Hazardous" means dangerous, which also doesn't match the context.

Answer:

B. Unconscious