Which of the following are prevented from entering the interstitial fluid of the brain, due to the blood-brain barrier?
a. waste products in the blood
b. some hormones
c. nicotine
d. alcohol

Which is it a characteristic of the animal kingdom? a. they include both vertebrates and invertebrates b. their skin is covered with hair or fur c. they are heterotrophs d. they are eukaryotic

Which statement describes john tuzo wilson’s contribution to the theory of plate tectonics?

Q: a: in sexually reproducing animals, once fertilization of the egg takes place, the exists as a single cell until cell division begins