Heyy i could use some help with this the questions kinda easy im just brain dead rn

Which would not reduce the amount of green house gasses in the air

22. the top of a cliff is located a distance h above the ground. at a distance h/2 there is a branch that juts out from the side of the cliff, and on this branch a bird's nest is located. two children throw stones at the nest with the same initial speed, one stone straight downward from the top of the cliff and the other stone straight upward from the ground. in the absence of air resistance, which stone hits the nest in the least amount of time?

Acar of mass 800kg is moving at a speed of 2.2m/s.