A positive control is a group in an experiment that receives a treatment with a known result, and therefore should show a particular change during the experiment. It is used to control for unknown variables during the experiment and to give the scientist something to compare with the test group.
Answer:
Both A and B
Explanation:
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Answer:
D The atrioventricular valve works as a rigid door to prevent water from escaping from the top.
Explanation:
the question is incomplete, but I annex the options and their explanation
When you compress the heart in this demo, why does the water leave the artery?
A It's like squeezing a sponge
B The arterial valve draws water from the ventricle.
C The atrioventricular valve has parachute-shaped fins to prevent water from escaping from the top.
D The atrioventricular valve works as a rigid door to prevent water from escaping from the top.
the atrioventricular valve during the contraction process closes at the top, thus avoiding the leakage of the liquid and leaving the artery that opens due to the force exerted by the volume and force of the ventricle.
