if you are riding on a train that speeds past another train moving in sam direction on an adjacent track it appears that other train is moving backward why?

i would think it's food chain

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide

it is a negative acceleration