Answer:
I would say the answer would be: 2. The heart contracts and expands to move blood.
Explanation:
The heart is forcing itself to contract and expand so it can move blood throughout the body. If I am wrong, let me know, but I believe that this is correct since it's a function of force.
There are different causes to error in measurement, most common are instrument precision and misreading the measurements. Some cases are from the experimenter judging to what they want rather than the reading itself.(no offense)
But... measurements are never accurate anyway, they're all estimations.
Pigments in photosystem 1 use energy from light to reenergize the electrons.
It would depend on what science the lab was researching/testing/studying
So if it was a chem lab it would have test tubes a Bunsen burner and chemicals
A, because after cell death there starts a new life for cells
