What has a range of sexual reproductive systems?
Options:
- (A) Computer systems.
- (B) Most plants
- (C) animals
- (D) Roundworms.
- (E) mammals
- (F) Art reproductions.
- (G) insects
- (H) Stuffed toy bears.
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Let's think first: Roundworms make up the phylum Nematoda. Within the Nematoda, a range of reproductive systems occur. A range of reproductive systems occur in roundworms.... So the answer is [(D)]

What are a source of food for many fish species?
Options:
- (A) layers of fat
- (B) bird species
- (C) human species
- (D) keystone species
- (E) Organic compounds
- (F) barnacles
- (G) gastropod shells
- (H) species of deer
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Let's think first: Sponges are a source of food for many species of fish. Sponges are also keystone species. Keystone species are a source of food for many fish species.... So the answer is [(D)]

What may vary in size as well as shape, but all are very small?
Options:
- (A) keeping food fresh for long periods of time
- (B) disease-causing microorganisms
- (C) A solid geometric shape
- (D) Unequal radiation absorption
- (E) Small countries.
- (F) Shapewear.
- (G) A water well.
- (H) Basic units of the plant body.
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Let's think first: Cells vary in size as well as shape, but all cells are very small. Basic unit of the plant body is the cell. Basic units of the plant body vary in size as well as shape, but all are very small.... So the answer is [(H)]

What is secreted by organisms like frogspawn to become a reef?
Options:
- (A) exocrine glands
- (B) food and shelter
- (C) exoskeleton
- (D) bones
- (E) Energy
- (F) Chemical energy
- (G) plasma
- (H) Energy.
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Let's think first: Many corals secrete an exoskeleton that builds up to become a coral reef. Good examples are Bubble coral, Elegance coral, Frogspawn and other Euphyllia corals. Organisms like frogspawns secrete an exoskeleton that builds up to become a reef.... So the answer is [(C)]

Hermatypic organisms provide what to many ocean organisms?
Options:
- (A) survival
- (B) food and shelter
- (C) competition
- (D) kinetic energy
- (E) produce light
- (F) important habitats
- (G) protect them
- (H) major threat to health
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Let's think first: Coral reefs provide food and shelter to many ocean organisms. Reef-building corals are hermatypic. Hermatypic organisms provide food and shelter to many ocean organisms.... So the answer is [(B)]

What is the effect of a population suddenly getting much smaller?
Options:
- (A) major threat to health
- (B) Decreased precipitation
- (C) a lot of human deaths
- (D) movement of tectonic plates
- (E) it is unpredicatbale
- (F) If they can no longer get food
- (G) Plant growth is reduced
- (H) enormous damage to homes
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Let's think first: Bottleneck effect occurs when a population suddenly gets much smaller. Effects of bottlenecks are unpredictable . When a population suddenly gets much smaller the effects are unpredictable.... So the answer is [(E)]