If the solar system were used as a model of an atom, what would the Sun most likely represent? OPTIONS:
- an ion
- a nucleus
- a neutron
- an electron
A: a nucleus

Scientists think that dolphins and whales may have evolved from a common ancestor. What evidence supports this hypothesis? OPTIONS:
- They swim the same way.
- They eat the same food.
- They live in the same area of the ocean.
- They have similar anatomies.
A: They have similar anatomies.

The number of squirrels in a certain ecosystem changes over time. These changes can be represented as a number of connected data points. Which method would a student most likely use to show this information? OPTIONS:
- pie chart
- line graph
- pictogram
- data table
A: line graph

Mammals must eliminate waste products that their bodies produce. Which organ helps mammals eliminate bodily waste? OPTIONS:
- appendix
- kidney
- pancreas
- stomach
A:
kidney