Question

Ik this isn't math but how do you write this? "These are some of the main reasons plants benefit human's lives." Or "These are some of the main reasons plants benefit humans' lives."

Answer 1

It would be your first example.

The 1st example is saying that this affects all humans. The 2nd example is saying it only affects a select few.

I hope this helps :)

Answer 2

The correct way to say it is.
These are some of the main reasons plants benefit humans' lives.