What is the function of heart valves

A) they prevent blood from flowing backwards

B) they force blood to flow out of the heart

C) they return blood to the heart

D) they regulate the heart rhythm

What is Inflammation? A. Is a tissue response to injury B. Is characterized by redness, swelling, heat and pain C. Is the body's first and foremost defense against infection D. A and B are correct E. A, B and C are correct

To be scientifically valid, a hypothesis must be

When a few intracellular mediator molecules activate several enzymes, and each of these activated enzymes activate still other enzymes, the hormone has initiated Select one: a. a cascade effect. b. a double loop effect. c. a protein kinase effect. d.

How does the composition of a typical lava dome differ from that of a typical fissure eruption?

Which of the species you germinated was a monocot? Which on was a dicot

A chipmunk's body uses multiple organs to absorb nutrients from a seed. Which statement correctly describes how two organ systems work together to absorb nutrients from the seed? A.

Suppose that in barley plants, the allele for tall stalks is dominant over short stalks and the allele for wide leaves is dominant over thin leaves.

Gamma rays and X-rays are similar because they both have? A. high frequencies and high energy. B. low frequencies and low energy. C. high frequencies and low energy. D. low frequencies and high energy.

Noise pollution from a racetrack is an example of a positive externality. t or f

What kind of organisms can be described as chemosynthetic?