The cell membrane protects the cell, separates the internal and external environments, and does not allow any material to enter or exit the cell.

In sexual reproducing animals once fertilization of the egg takes place, the exists as a single cell until cell division begins. a) egg b) larva c) sperm d) zygote

The fish shown above is a tarpon. it is a fast-swimming and powerful open-water fish. its closest relatives, oddly, are burrow-dwelling conger eels that stay on the bottom. both eels and tarpon developed from snake-like larvae that float in the plankton during the first stages of life. once they mature, tarpon and eels are not found near one another in the ocean. the tarpon and the eel illustrate all of the following except

Which worm has eyespots that are used to detect light? a fluke b marine worm c planarian d tapeworm