What do simple eukaryotes have?
Options:
- (A) Energy
- (B) fur and fat
- (C) Motility
- (D) bioaerosols
- (E) four limbs
- (F) pollen
- (G) glucose
- (H) Energy.
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Let's think first: Most protists have motility. Protists are the simplest of eukaryotes. The simplest eukaryotes have motility.... So the answer is [(C)]

Biomass is the total mass of living things at each what?
Options:
- (A) trophic level
- (B) important habitats
- (C) Energy.
- (D) food and shelter
- (E) Power plants
- (F) animals
- (G) body water
- (H) heat energy
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Let's think first: Biomass is the total mass of organisms at a trophic level. Most living things are called organisms. Biomass is the total mass of living things at a trophic level.... So the answer is [(A)]

What body part would be attached to the external framework?
Options:
- (A) heart
- (B) insects
- (C) respiratory system
- (D) wings
- (E) humans
- (F) Tail
- (G) fat
- (H) digestive system
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Let's think first: Wings are part of the exoskeleton and attached to the thorax. An exoskeleton is an external framework. Wings are part of the external framework.... So the answer is [(D)]

Evolution is a change in the genetic traits of living things over what?
Options:
- (A) universes
- (B) HIV
- (C) long
- (D) extinct organisms
- (E) dead things
- (F) time
- (G) H 2 O
- (H) years
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Let's think first: Evolution is a change in the characteristics of living things over time. Almost all physical characteristics are genetic traits, inherited from parents. Evolution is a change in the genetic traits of living things over time.... So the answer is [(F)]

Thyroxine increases the rate of metabolism in cells throughout the what?
Options:
- (A) Summer
- (B) body
- (C) state
- (D) skin
- (E) H 2 O
- (F) HIV
- (G) life
- (H) humans
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Let's think first: Thyroid hormones increase the rate of metabolism in cells throughout the body. Thyroxine, a thyroid hormone, is an aryl iodide. Thyroxine increases the rate of metabolism in cells throughout the body.... So the answer is [(B)]

An animal which may have one or two hearts to pump blood is:
Options:
- (A) squid
- (B) goats
- (C) bats
- (D) mammals
- (E) toads
- (F) Birds
- (G) edible
- (H) a fish
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Let's think first: Mollusks have a circulatory system with one or two hearts that pump blood. Interestingly, a squid is also a mollusk. Squid have a circulatory system with one or two hearts that pump blood.... So the answer is [(A)]