The light of dawn and the buzz of an alarm clock lead to wakefulness through the

Reticular activating system is the correct answer.

The reticular activating system is a very complex network of neurons located in the brainstem that is responsible for regulating arousal, alertness and sleep-wake transitions. This system is very important to the human body, if damaged it can result in coma, lethargy or sleep problems.

d is the correct answer.

b is incorrect because it makes food by itself

c is incorrect because us humans don't know how to produce their own food using the sun like plants.

a is incorrect because consumers can depend on carnivores for eating food for consumers to eat the dead organism. same thing with omnivores.