How can scientists use fossils in rock layers as evidence that one event happened earlier than another event?

It  usually would depend on the strata, which are layers of rock, to know fossil age by looking at them, if a fossil was more on the top of the strata than another one, it’s the later one

Explanation:

Hope this helps!

Mark brainliest please but only if you would like to.

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .

b i think it’s a water wheel turning in a stream