Astudent observed that every time the temperature rises above 90 degrees, he forgets to take out the trash. based on this observation he concluded that temperatures above 90 degrees result in temporary memory loss. in actuality, the student:

is suffering from dehydration

Explanation:

When the environmental temperatures, the human body needs more water because the rate at which it looses water is faster in comparison with winter days.

Water is the most basic liquid that our body needs to work efficiently. There are different effects of the water lost like headaches, dry mouth, dry skin, etc.

Headaches is one symptom, since the brain is covered practically with water, when doesn´t have enough liquid it starts to receive the signal and in response pain is release.

a is the answer i believe.