Creatures with six legs may live in what?
Options:
- (A) space centers
- (B) ocean water
- (C) salt and water.
- (D) large colonies
- (E) small pendants
- (F) loose soil
- (G) distant moons
- (H) body water
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Let's think first: Insects may live in large colonies and have complex social behaviors. Insects have six legs. Creatures with six legs may live in large colonies.... So the answer is [(D)]

What is an example of a tetrapod vertebrate that produces amniotic eggs.
Options:
- (A) animals
- (B) tortoises
- (C) crocodiles
- (D) barnacles
- (E) insects
- (F) parasites
- (G) Lizards
- (H) a fish
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Let's think first: Reptiles are a class of tetrapod vertebrates that produce amniotic eggs. All lizards are reptiles. Lizards are tetrapod vertebrates that produce amniotic eggs.... So the answer is [(G)]

What occurs when cell walls ease up?
Options:
- (A) root growth
- (B) air cools
- (C) dilation
- (D) sweating
- (E) Dehydration
- (F) recovery
- (G) Exfoliation
- (H) less water
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Let's think first: Dilation occurs when cell walls relax. Slowly leg muscles ease up and shoulders relax. Dilation occurs when cell walls ease up.... So the answer is [(C)]

What crawls and is known to have a complex nervous system?
Options:
- (A) fur seals
- (B) Insects.
- (C) mammals
- (D) animals
- (E) a fish
- (F) humans
- (G) bees
- (H) ducks
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Let's think first: Most invertebrates have a more complex nervous system. Insects are the most common invertebrates. Insects have a more complex nervous system.... So the answer is [(B)]

What harms the respiratory and circulatory systems?
Options:
- (A) oil
- (B) rain
- (C) sulfur
- (D) cars
- (E) tires
- (F) coal
- (G) tar
- (H) bicycles
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Let's think first: Air pollution harms the respiratory and circulatory systems. Cars are a significant source of air pollution. Cars harm the respiratory and circulatory systems.... So the answer is [(D)]

What do plants respond to?
Options:
- (A) Energy.
- (B) heat produced
- (C) Chemical energy
- (D) sun's heat
- (E) the environment
- (F) heat energy
- (G) Sulfur dioxide
- (H) temperature
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Let's think first: Plants respond to daily and seasonal cycles and to disease. Temperature follows a seasonal cycle. Plants respond to temperature.... So the answer is [(H)]