Answer:
Soil getting dug up by moles.
Chromosomes are lined up in the middle of the cell during metaphase.
To be honest, since we live on Earth (assuming you do as well), Earth is the easiest planet to study. We don't know much about the other planets because we've never been to any of them. I believe that the second easiest planet to study is either Uranus or Saturn.
Carbon dioxide is released by animals.
What sample are you talking about?
