Blood vessels that contain valves and rely on skeletal muscles to move blood are called: A) arterioles
B) veins
C) capillaries
D) arteries

and why!? thanks!!

How many cells are our body made of ? ♡

The graph below compares the rates of reaction of a burning candle and an exploding firework. comparing chemical reactions what can you conclude from the graph? the reaction that causes a firework to explode requires less energy to start, and occurs more rapidly than the reaction that causes a candle to burn. the reaction that causes a firework to explode requires less energy to start, and occurs less rapidly than the reaction that causes a candle to burn. the reaction that causes a firework to explode requires more energy to start, and occurs less rapidly than the reaction that causes a candle to burn. the reaction that causes a firework to explode requires more energy to start, and occurs more rapidly than the reaction that causes a candle to burn. mark this and return

With regard to enzymes, key is to lock as a) substrate is to activation energy eliminate b) product is to substrate. c) enzyme is to active site. d) substrate is to active site.