What breathes with gills as larvae and with lungs as adults.
Options:
- (A) Salmon.
- (B) Frogs.
- (C) parasites
- (D) Whales.
- (E) Mice.
- (F) a fish
- (G) air
- (H) tortoises
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Let's think first: Most amphibians breathe with gills as larvae and with lungs as adults. All frogs are amphibians. Most frogs breathe with gills as larvae and with lungs as adults.... So the answer is [(B)]

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.
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Let's think first: Marine species live mainly in shallow coastal waters. Most marine organisms live near the surface. Most organisms live mainly in shallow coastal waters.... So the answer is [(A)]

What causes h20 to expand when frozen?
Options:
- (A) evaporation
- (B) vaporization
- (C) hydrogen bonds
- (D) helium bonds
- (E) mysterious forces
- (F) nitrogen bonds
- (G) Physical weathering
- (H) precipitation
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Let's think first: Hydrogen bonds cause water to expand when it freezes. Water is everywhere H20. Hydrogen bonds cause H20 to expand when it freezes.... So the answer is [(C)]

Behaviors can be learned through what?
Options:
- (A) competition
- (B) quitting
- (C) A computer
- (D) disappearing
- (E) changing sizes
- (F) exercise
- (G) animals
- (H) fun games
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Let's think first: Behaviors can be learned through play. Games are fun to play. Behaviors can be learned through fun games.... So the answer is [(H)]

The sun contributes what to ecosystems?
Options:
- (A) sun spot
- (B) energy
- (C) darkness
- (D) seeds
- (E) positive
- (F) photons
- (G) Nutrients
- (H) Energy.
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Let's think first: Energy enters ecosystems in the form of sunlight or chemical compounds. If there is sun, there is sunlight, there is day. Energy enters ecosystems from the sun.... So the answer is [(B)]

What are behavior that is intended to attract a mate?
Options:
- (A) a doorbell
- (B) firm hugs
- (C) Complex rituals
- (D) Riding a bike
- (E) Behaviour modifications
- (F) Magnets
- (G) honeybees
- (H) Friendship
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Let's think first: Courtship is behavior that is intended to attract a mate. Complex courtship rituals precede mating. Complex rituals are behavior that are intended to attract a mate.... So the answer is [(C)]