Select each correct answer.
by comparing fossils in higher sedimentary layers with fossils in lower sedimentary layers, scientists can learn which of the following?

select one or more:
a. the relative age of different species
b. which types of organisms were more common during various time periods
c. how species have evolved over time

A.

Explanation:

because if they are at different layers in the ground that must mean that they died differently. Which also means that they died at different times which means that they are different amount of years old.

regulation of gene expression. gene expression can be regulated by various cellular processes with the aim to control the amount and nature of the expressed genes. these regulatory proteins bind to dna and send signals that indirectly control the rate of gene expression

explanation: