Which organism belongs in the kingdom Protista?
A: paramecium

Which of the following keeps the planets in our solar system in orbit around the Sun?
A: gravitational force

A geologist finds a layer of shale near the surface from a certain time period. Nearby, the geologist finds the same layer of shale, but it is deeper underground than the first layer. What might have caused the difference in the depth of the shale layer?
A: a fault

In the past, wild hogs called "javelinas" were seen only in the southern part of New Mexico. Now, javelinas are seen in areas 100 miles further north. What is the most likely cause of this expansion?
A:
Environmental conditions have changed.