The danger posed to fish in an aquarium by an overpopulation of bacteria caused by an algal bloom is most likely a OPTIONS:
- decrease in water temperature.
- reduction in oxygen levels.
- decrease in food supply.
- removal of minerals.
A: reduction in oxygen levels.

Which property of water can cause a rock to break apart? OPTIONS:
- Water boiling at 100C.
- Water losing energy slowly.
- Water expanding as it freezes.
- Water having a high surface tension.
A: Water expanding as it freezes.

The brown tree snake is a nonnative species found on the South Pacific island of Guam. The brown tree snake population in Guam is so large that it negatively affects the humans there. Which statement best explains why the brown tree snake has flourished in Guam? OPTIONS:
- There are many animals for food.
- There are no natural snake predators.
- The climate is ideal for snake reproduction.
- The vegetation provides good habitat for hunting.
A: There are no natural snake predators.

The spectrum of visible light can be seen in a rainbow because white light is OPTIONS:
- reflected and transmitted.
- refracted and dispersed.
- absorbed and diffracted.
- produced and emitted.
A:
refracted and dispersed.