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

Next pretest: evolution select the correct answer in a laboratory population of flies, the female flies are gray and the males are yellowish gray. biologists observed that all the male flies had an equal chance for reproduction, but the male flies with the brightest colors were more likely to successfully reproduce. what phenomenon could explain such a change? a sexual selection b. disruptive selection c. stabilizing selection d. directional selection

List the advantages and disadavantages of the switch from persistent chlorinated hydrocarbon pesticides (such as ddt) to nonpersistent organophosphate pesicides. have the benefits of the switch outweighed the disadvantages? explain.

Protein synthesis actually begins in the nucleus when transcribes a single gene on the dna molecule is copied. the process of copying this gene is called this copy is known as and contains the protein building instructions. this copy is sent out into the cytoplasm to the part of the cell known as the the of the ribosome will join together to form a functional ribosome when they attach to the mrna. as the mrna moves through the ribosome, the message is read by transfer rna brings the correct back to the ribosome. the amino acids are placed in the correct order and are hitched together by