Agalaxy cluster is a. another name for a star cluster. b. a group of stars that cluster just outside a galaxy. c. another name for the milky way. d. a group of galaxies bound together by gravity.

Which class of organic compounds makes up the channels and pumps that move materials from one side of the cell membrane to the other? a.) carbohydrates b.) lipids c.) proteins d.) nucleic acids

Hummingbirds drink nectar from flowers, while robins eat plant seeds. what does this reduce?

Models are non-visual ways of coummincating how someone thinks about something in the natural world