A measure of the amount of the light given off by a star is its .
a.

apparent magnitude

c.

position in space
b.

absolute magnitude

d.

size

What is the primary function of the nervous system?

Read each description below and determine to which stage of sleep each pertains. then click and drag each box into the appropriate category below.

When is your breathing likely to speed up? a. when your white blood cells increase b. when your cells need more energy c. when your heart cells need more carbon dioxide d. when your blood cells have too much oxygen