It specifies what exactly the variations are of whatever population is being examined.
As newer rock layers form, they overlap with the ones with the pre-existing ones. Therefore, when looking for older rock layers, we would look for the ones that are deeper beneath the surface of the earth. On the other hand, newer rock layers are found at the top. This is also observed in the fact that oil rigs dig very deep into the ground to access the layers that are millions of years old.
6 is true - scientists with a strong belief in what they are working on may show bias
7 is false - most plants and animals reproduce sexually
The central nervous system and the peripheral nervous system
