Dan was running, and he tripped and hurt his knee. The pain signals were carried to his brain by the:

A. sympathetic nervous system.

B. central nervous system.

C. endocrine system.

D. lobes of the brain.

How is scientific work different from nearly all other human activities?

List five plants that live in the biome

What two layers of the egg must the sperm penetrate to reach the egg's plasma membrane?

What is the relationship between diversity and survival of a species? (choose all that apply) With increased diversity, there is increased survival rate With increased diversity, there is decreased survival rate With decreased diversity, there is

Assume that a black guinea pig crossed with an albino guinea pig produced five black offspring. When the albino was crossed with a second black one, 4 black and 3 albino offspring were produced.

How and why does soil and water heat and cool differently and how that affects the air above it

What is the adaptive (natural selection) benefit of the diving response in aquatic and marine mammals? do you think it has an adaptive purpose in humans of is it just a remnant of our evolutionary past?

What happens to the density of the Earth's Layers as you move towards the core of the earth

In humans, what is the results when a valve is leaking blood backward in the heart

The spindle forms during this phase