How do you tame a horse in
and why should i never use my diamonds on a farming tool? ?

taming - by feeding it something. you'll see the hearts appear, and after a while, it will be tamed. then, to ride it, you'll need a saddle.

as for the diamonds, that's a waste, bkz the work is done best by iron.

the answer is d. chordata

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.