Which of the following best explains the movement of DNA during gel electrophoresis? A. Since restriction enzymes cut DNA into differently sized pieces, polymerase is able to move the fragments through the gel.
B. Since polymerase enzymes cut DNA into differently sized pieces, restriction enzymes are able to move the fragments through the gel.
C. Since DNA is positively charged it attracts toward the negative end of the gel plate.
D. Since DNA is negatively charged it attracts toward the positive end of the gel plate.

A. Since restriction enzymes cut DNA into differently sized pieces, polymerase is able to move the fragments through the gel.

Explanation:

a long strand of spaghetti is folded once. if this is cut 20 times, how many pieces of spaghetti will there be? a long strand of spaghetti is folded once. if this is cut 20 times, how many pieces of spaghetti will there be? a long strand of spaghetti is folded once. if this is cut 20 times, how many pieces of spaghetti will there be? a long strand of spaghetti is folded once. if this is cut 20 times, how many pieces of spaghetti will there be? a long strand of spaghetti is folded once. if this is cut 20 times, how many pieces of spaghetti will there be?

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air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.