Eons, eras, periods, and epochs, are all examples of .

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?

What do all macromolecules have in common with each other? oa. they all are formed from the same elements. ob. they all have major roles in cell membranesoc. they all act as catalysts in the body. od. they all have peptide bonds between carbon atoms.

Which is an example of a decomposer? a. bear b. algae c. grass d. bacteria d bacteria