Solution idea: All chemical reactions require activation energy to get started. Chemical equations describe chemical reactions. Chemical equations describe something that requires activation energy to get started.
Q: What describes something that requires activation energy to get started?
Options:
- (A) igniting fuel and oxidiser
- (B) heating liquids
- (C) Fully cooking the oysters
- (D) Riding a bike
- (E) an engine
- (F) burning coal
- (G) chemical equations
- (H) Firecrackers
A: (G)

Solution idea: Pneumonia may be caused by an infection or injury of the lungs. Streptococcal pneumonia is caused by the bacteria Streptococcus pneumoniae. Streptococcus can infect the lungs following injury.
Q: What can make lungs more at risk for infection by streptococcus?
Options:
- (A) Allergies
- (B) bacteria
- (C) Pollution
- (D) injury
- (E) fungi
- (F) sweating
- (G) the skin
- (H) smoking
A: (D)

Solution idea: Running water is better able to dissolve oxygen and nutrients than standing water. Also, running water in rivers is the major force of erosion on the surface of the earth. Rivers are better able to dissolve oxygen and nutrients than standing water.
Q: Which body of water would be able to dissolve oxygen and nutrients the best?
Options:
- (A) NaCl
- (B) Lake
- (C) Puddle
- (D) Pond
- (E) rain
- (F) CO 2
- (G) River
- (H) sugar
A: (G)

Solution idea: Echinoderms lack a centralized nervous system. Echinoderms are represented by the starfish. Starfish lack a centralized nervous system.

Q: What is something missing in starfish?
Options:
- (A) the body's largest organ
- (B) centralized nervous system
- (C) characteristics
- (D) layers of fat
- (E) permineralization
- (F) biological diversity
- (G) kinetic energy
- (H) A compound that donates proton
A: (B)