Problem:OPTIONS:
- toxic rain
- ozone
- hail
- acid rain

Answer the following question given this paragraph: Acid rain is rain that has a pH less than 5. It forms when nitrogen and sulfur oxides dissolve in rain. Acid rain kills living things and damages buildings and statues. Q: What is formed when nitrogen and sulfur oxides dissolve in rain? A:
****
A: acid rain

Problem:OPTIONS:
- they multiply
- they pop
- they get smaller
- they get bigger

Answer the following question given this paragraph: Gas bubbles get bigger when they are under less pressure. Q: If everything in a system stays the same but the pressure deceases, gas bubbles will change in what way? A:
****
A: they get bigger

Problem:OPTIONS:
- gases and animals
- plants and water
- soil and animals
- plants and animals

Answer the following question given this paragraph: Fossil fuels are made from plants and animals that lived hundreds of millions of years ago. The plants and animals died. Their remains settled onto the ground and at the bottom of the sea. Layer upon layer of organic material was laid down. Eventually, the layers were buried very deeply. They experienced intense heat and pressure. Over millions of years, the organic material turned into fossil fuels. Q: Fossil fuels are made out of what two objects? A:
****
A: plants and animals

Problem:OPTIONS:
- spontaneous mutation
- mass extinction
- natural selection
- secondary succession

Answer the following question given this paragraph: Secondary succession occurs in a formerly inhabited area that was disturbed. Soil is already in place, so pioneer species include small plants such as grasses. Q: What occurs in a formerly inhabited area that was disturbed? A:
****
A:
secondary succession