How do skeletal muscles contribute to blood flow? a. skeletal muscles force blood in veins to return to the heart b. skeletal muscles prevent blood in arteries from traveling backwards c. skeletal muscles force the blood in capillaries into cells d. skeletal muscles increase the blood pressure in arteries

Identify the various levels of atmosphere. troposphere mesosphere exosphere stratosphere thermosphere

Which of the following is a difference between active transport and facilitated diffusion? view available hint(s)which of the following is a difference between active transport and facilitated diffusion? facilitated diffusion can move solutes against a concentration gradient, and active transport cannot.active transport involves transport proteins, and facilitated diffusion does not.facilitated diffusion involves transport proteins, and active transport does not.active transport requires the expenditure of cellular energy, and facilitated diffusion does not.

What did not occur in the proterozoic eon a)the oxygen levels increase greatly in the atmosphere,b)the emergence of the eukarya , c)muti cella’s eukaryotic organisms began to diversify,d)anaerobic bacteria kept thriving with more oxygen