Cap on the head of the sperm that contains enzymes.

In general, the endocrine system is faster and more specific than the nervous system.

A population in which death rates are higher than birth rates and the prereproductive group is smaller than the reproductive group is best represented by an age structure diagram with a pyramid shape.

Eats both producers and consumers.

Which of the following senses would involve a chemoreceptor?

Wetland dominated by trees.

Which of the following diseases is characterized by collapse of the bronchioles causing the alveoli to distend to the point of rupture?

The urinary bladder is useful because it:

The sense of smell uses photoreceptors.

Approximately how far does a red blood cell travel in the bloodstream before it is worn out and is removed?