[Q] Nematodes reproduce how?
Options:
- (A) root growth
- (B) heat or cold
- (C) pollen
- (D) electrically
- (E) sexually
- (F) seeds
- (G) survive
- (H) a cuticle
[A] Here's my solution: Roundworms reproduce sexually. Nematodes are millimeter-sized roundworms. Nematodes reproduce sexually. The answer is (E).

[Q] Most organisms live mainly in
Options:
- (A) shallow coastal waters
- (B) the environment
- (C) soil
- (D) trees
- (E) Earth orbiting the Sun
- (F) ocean water
- (G) plasma
- (H) salt and water.
[A] Here's my solution: Marine species live mainly in shallow coastal waters. Most marine organisms live near the surface. Most organisms live mainly in shallow coastal waters. The answer is (A).

[Q] What detects hybrids of the substance that helps assemble proteins?
Options:
- (A) orchids
- (B) sensory neurons
- (C) peachleaf willow
- (D) luminometer
- (E) A computer
- (F) animals
- (G) A Greek letter
- (H) scattered light
[A] Here's my solution: DNA contains genetic instructions for proteins, and RNA helps assemble the proteins. RNA hybrids are then detected by a luminometer. A luminometer detects hybrids of the substance that helps assemble proteins. The answer is (D).

[Q] Objects that are a few nanometers in size can be seen only with:
Options:
- (A) an electron microscope
- (B) refraction of light
- (C) matter vibrating
- (D) ultrasound
- (E) The bending of a ray of light
- (F) slight magnification
- (G) flashlights
- (H) lens
[A]
Here's my solution: Viruses are so small that they can be seen only with an electron microscope. Viruses Viruses are very small, a few nanometers in size. Objects that are only a few nanometers in size can be seen only with an electron microscope. The answer is (A).