Which underwater organism shares a symbiotic relationship with whales?

Abacteriophage typically attaches to the bacterium and then

Which of the following may one conclude from a map that shows the average ph value of rainfall in the u.s.? acid rain is a more serious problem on the east coast. acid rain falls equivalently across the continental u.s. there are more factories on the west coast. the midwest has fewer forests than the rest of the u.s.

Which characteristics must an object possess in order to be considered alive?