One parrot species that feeds on large seeds nests is in the same tree as a parakeet that feeds on small seeds. how are the birds able to coexist?
a) they occupy different niches.
b) they occupy different habitats.
c) they occupy different ecosystems.
d) they occupy different communities.

There is a liquid capsule inside a cup full of liquid. the cup full of liquid has salt in it and the liquid capsule has no salt in it. in which direction will the solvent flow? a. the salt does not have to move b. from the capsule to the larger cup c. equally between the capsule and the cup d. from the larger cup to the capsule

For a comparative or experimental investigation, scientists often make a testable about a scientific question, and then they test it in the investigation. a. control b. hypothesis c. procedure d. system

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?