Explain how the ability to describe the pattern of ice ages over the past million years helps us to assess what is a “normal” variation in Earth’s atmosphere.

Which is the best example of plant tissue? the answer is d (just took the test)

Why do mountaineers become breathless as they reach high altitudes

Question 17 (1 point) where does penicillin come from? a. it is a chemical that man invented b. it is a fungus c. it is a toxin made by other bacteria d. it was discovered in archaebacteria