Q: Fact 1: The emission of sulfur dioxide causes acid rain. Fact 2: The sulfur dioxide is converted into sulfuric acid. Given the two facts above, what causes acid rain? | OPTIONS:
- gases
- rainfall
- Pollution
- fossil fuels
- emissions
- vehicles
- burning
- wind
A: emissions

Q: Fact 1: Seed dispersal has a positive impact on a plant. Fact 2: Grape seeds are dispersed by animals. Given the two facts above, what has a positive impact on plants? | OPTIONS:
- Roundworms
- Enzymes
- growth
- hurricane
- animals
- fire
- sugar
- earthquake
A: animals

Q: Fact 1: Reproduction is the process by which organisms give rise to offspring. Fact 2: Mutations are sources of variations in offspring. Given the two facts above, what can happen during the reproduction process? | OPTIONS:
- tree falls
- Mutations
- Plants growth
- movement
- competition
- adding heat
- contamination
- Dehydration
A: Mutations

Q: Fact 1: Bivalves feed on plankton and nonliving organic matter. Fact 2: Bivalve molluscs are very common. Given the two facts above, what feeds on plankton and nonliving organic matter? | OPTIONS:
- bacteria
- barnacles
- animals
- sharks
- pythons
- graptolites
- molluscs
- bears
A: molluscs