green grass needs to be cut regularly. why does pubic hair reach a certain length and appear to stop growing?

Answer 1

I don't see what grass has to do with this, but...
All of the hair on your body has a genetically programed length cycle. For example, the hair on a persons head, generally grows for about 7 years, then it stays put for a few more years before falling out. How long your hair growth cycles are, how fast your hair grows, and how long it stays on you before it falls off are all genetically programed into every hair follicle on your body. The hair on a persons arm doesn't grow for as many years as the hair on a persons head etc. The cycles are individual to the part of the body, and even to the individual hairs themselves. This is why some people can grow their hair longer than others. It's also why some people have freakishly long hairs in odd places on their body. (I have a friend who has a REALLY long eyebrow hair LOL) It's genetics.

Answer 2

its mainly because of sex hormone androgen