Neurons and some other specialized cells divide infrequently because they

 The correct answer is :  have entered into G0

Explanation:  G0 is the fifth phase, it is named because it is out of the cycle, it is still for an undefined time when new cells are not needed and in this phase the cell is not in division and has lost the ability to perform mitosis.

there are no contact forces mentioned on the list of choices that you've provided.

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.