Reason is humans have not yet completed demographic transition
Answer:
Do you mean planets?
if so,The heavy rocky particles within the inner part of the disk formed planetesimals and eventually, inner planets. In our solar system, the four innermost planets Mercury, Venus, Earth and Mars are known as inner planets. They lie inside the asteroid belt. They have volcanoes and valleys and are very hot compared to outer planets.Inner planets are much smaller than the outer planets, and are rocky with an iron core.
Hope that helps!
A. Bacteria are single-celled.
I think it would be this because humans have way more than one cell, and the other ones are the same as us.
Just guessing
By dividing the mass and density, you get volume
