B. 7
the atomic mass is protons + neutrons.
I'm pretty sure it's <span>both. Allopatric speciation occurs when there is a physical barrier formed like a mountain or river. and Sympatric speciation occurs when there is a genetic barrier formed like a mutation that causes a different mating season or preference in mate choice.
hope this helps!</span>
Answer:
D. We know more about the Cenozoic era because this the most recent time period in the history of the Earth, and we have more information available to study.
Explanation:
The Cenozoic era is the era that is by far the best studied and known by the scientists. The main reason for this is that this era is the most recent one, and it is actually the era we live in. Because it is the most recent era, the Cenozoic is abundant with lot of evidence of what has happened in it. The fossil records are very rich as the fossils didn't had that much time to totally decompose. The rock layers are much younger, so they contain much more detailed evidence of the plant life, climate, changes in the environment. The oceanic crust is also in abundance, which is not the case with the other eras as the oceanic crust is constantly suducted.
True cause like bugs and stuff
