It could possibly harm other plants and if those plants become less and are a good source for animals, the animals would most likely die
Gravitational waves are ripples in spacetime. They are created whenever objects with mass move. Hope this helps :)
Your hypothesis is incorrect considering every day has the same length to it.
One reason is for safety! in case you get stranded in a body of water you can keep yourself afloat
Maybe biosphere and geosphere?
