Q: Fact 1: Ejaculation occurs when muscle contractions propel sperm from the epididymes. Fact 2: Bacteria usually cause epididymitis. Given the two facts above, bacterial infection can inhibit ejaculation of what? | OPTIONS:
- babies
- sperm
- sugar
- animals
- erection
- eggs
- humans
- pregnancy
A: sperm

Q: Fact 1: Biodiversity increases the productivity and stability of ecosystems. Fact 2: An ecosystem includes the organisms and their habitat. Given the two facts above, what does biodiversity increase the productivity and stability of? | OPTIONS:
- density
- the looseness of soil
- water vapor
- the environment
- h2o
- swamp vegetation
- biological diversity
- organisms and their habitat
A: organisms and their habitat

Q: Fact 1: Mutations are essential for evolution to occur. Fact 2: Mutations Mutations are caused by random changes in genes. Given the two facts above, what is essential for evolution? | OPTIONS:
- hurricanes
- that material's properties
- remains of prehistoric life
- the body's largest organ
- revolutions
- Plant reproduction
- natural disasters
- random changes in genes
A: random changes in genes

Q: Fact 1: Adoorbell converts electrical energy into sound. Fact 2: Perception of sound Sound is a wave. Given the two facts above, what does a doorbell convert energy into? | OPTIONS:
- nerves
- energy
- light
- heat
- nest
- houses
- waves
- organ
A: waves