Which best describes a theory?

A. a well-supported conclusion

B. a proven fact

C. an educated guess

D. an untested claim

What is ventilation to with the lungs?

Wind energy is plentiful in regions with vast open spaces it is a non polluting renewable resource what could be an economic factor that makes the use of this resource less feasible then non renewable resource even in such regions

Why are mushrooms important to the food chain? A. They recycle nutrients into the ecosystem. B. They produce food energy for other living things. C. They recycle oxygen into the atmosphere. D. They consume excess herbivores in the ecosystem.

What determines how many covalent bonds two atoms can make?

What are some of the possible consequences of mutations

Which traight was important in the advancement of modern fish

The atoms surrounding an edge dislocation experience what kind (s) of strain (s) ?

How is water conserved on a space station?

Where are dunes most commonly located, country and state, not environment.

Which of the following is not associated with the stomach? a. alcohol absorption b. gastric glands c. duodenum d. pepsin?