The first energy level of an atom can hold 2 electrons.  All other energy levels hold ___ electrons.

Which of the following pH values is considered acidic?

Atoms with the same atomic numbers but different number of neutrons are called _____________. Some may be unstable and radioactive

Which of the following is not one of the three domains?

In comparative anatomy, structures that are anatomically similar because they come from a common ancestor (like the bones that make up the flipper of a whale and wing of a bat) are known as:

The ability to breed and produce viable, fertile offspring defines a(n):

When the hydrogen of one water molecule is attracted to the negative portion of another molecule, this is known as a __________ bond.

Which is the correct levels of organization for living organisms (from simplest to most complex)?

Kingdom that contains organisms that are multicellular and are photosynthetic (autotrophs).

Which plot(s) would answer the following questions: How does the distribution of penguin heights compare for species?