Veins have a much lower blood pressure than arteries. which of these prevents backflow of blood in veins? a. pressure applied by the heart b. one–way valves in veins c. thin muscular walls of veins

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

Astudent completed a lab report. which correctly describes the difference between the "question" and "hypothesis' sections of her report? "question states what she is asking, and "hypothesis" states the result of her experiment "question" states what she is asking, and "hypothesis" states what she thinks the answer to that question is in 'if. then because" format. "question" describes what she is trying to find out, and "hypothesis" states the procedures and methods of data collection. "question" describes what she is trying to find out, and "hypothesis" states any additional information or prior knowledge about the question

Cells control gene expression at which steps