How do astronauts prevent muscle atrophy?
a. they sleep more.
b. they exercise
c. they sleep less
d. they eat alot

Match the examples to the correct level of organization. 1. system level roses, snakes, puppies 2. organism level roots, stamens, leaves 3. tissue level bone, cartilage, blood 4. organ level heart, veins, arteries

As a small change in a person's dna can cause a genetic disorder

Select the word from the list that best fits the definition a system made of 25 satellites