Why might a scientist repeat an investigation and not get the same results?

Marianne is comparing two animals: a fruit fly and a fruit bat. she asks, "do a fruit fly and a fruit bat share a common ancestor in their evolutionary history? " according to evolutionary theory, what is the answer to marianne's question?

How do temperature and salinity affect deepwater currents? question 15 options: as temperatures and salinity levels of water increase, the water rises to the surface where it creates currents as it moves to colder regions. they create changes in wind direction, moving denser water in the same direction as the wind and causing the deepwater circulation patterns found in the ocean. they equalize the forces on undersea currents caused by the coriolis effect as they replace more dense water with less dense water. they create density differences that cause dense deepwater currents to flow toward the equator where they displace less dense, warmer water above them.

In what ways does the study of human population differ from the study of wildlife ecology