Answer:
Because if your not participation your not getting any excercise physically or mentally
If some living things do not reproduce this could be considered a defect or a genetic mutation in those people. If we take humans for example, if most humans reproduce and some don't because they cannot (if a guy cannot produce sperm) this doesn't mean that he isn't alive, it just means he was born with a genetic mutation which doesn't allow him to produce sperm needed for reproducing.
In a negotiation, “the bottom line” refers to the value of the negotiation... all too often novice negotiators spend a great deal of time trying to determine the true financial value of each of the items that are being negotiated