What does a cell nucleus do? Select one:
a. control everything the cell does
b. surround the cell
c. hold important chemicals the cell needs
d. protect the cell.

Which of the following involves only abiotic factors? a. a large rock being weathered by wind and rain b. an otter using a stone to break open a sea urchin c. a spider building a web in the corner of a building d. a pine tree absorbing light from the sun