Biology Question:

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Answer #1
If it did not twist, would you expect it to fit into the miniscule cell? As we all know, if we join all of the DNA molecules from a person's body end to end, we would get length three times the distance from the centre of the earth to the sun! Therefore, DNA does not have a choice but to follow the super solenoid structure. This is also aided by the purine-pyrimidine linkages, to balance the weight of DNA components. Why pressing down on the cover slip does not remove excess water. Because of Newton's Third Law of Motion: Every action has an equal an opposite reaction and hydraulic pressure. When you press down on the cover slip, the water underneath it pushes back against you with the same force that you are pressing down on it. If you want to get the water to move out from under the cover slip, you need to direct it to the side. One way to do this is to lift an edge and break the suction, then set it back down on one edge first to let the water run out, then press it down. This creates a side motion so the water does not push straight up into the cover slip, but pushes at an angle, which allows it to run out.

Answer #2
The same principle applies to squeezing an egg. If you squeeze an egg in your hand with even pressure all the way around, it will not crack because the eggshell presses back into your hand with the same pressure. The pressure is so evenly distributed around the egg that it resists breaking. However, if you hold it with more pressure going into it from a side angle, like only squeezing a part of the egg, then it will break. That is the same idea as the cover slip; if you use an angle from the side, the force pushing back at you that does not have support so it allows the water to leak out.