What can be reduced when a population suddenly gets much smaller?
Options:
- (A) Pollution
- (B) The size of the Earth
- (C) Greenhouse gasses
- (D) The size of bottlenecks
- (E) The size of the environment
- (F) Genetic variation
- (G) Plant growth is reduced
- (H) Quality of life
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Let's think first: Bottleneck effect occurs when a population suddenly gets much smaller. Genetic variation can be reduced by random genetic drift, population bottlenecks, founder effect. Genetic variation can be reduced when a population suddenly gets much smaller.... So the answer is [(F)]

Most of what type of animal is known for having a shell?
Options:
- (A) fossils
- (B) toads
- (C) eggs
- (D) swea
- (E) small
- (F) insects
- (G) porous
- (H) snail
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Let's think first: Most mollusks have shells. Among mollusks, the golden snail is a survivalist. Most snails have shells.... So the answer is [(H)]

What regrows broken off segments of itself?
Options:
- (A) barnacles
- (B) teeth
- (C) roots
- (D) earthworm
- (E) Leptospirosis
- (F) spiders
- (G) cells
- (H) root growth
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Let's think first: Annelids have the amazing capacity to regrow segments that break off. Earthworms are annelids meaning segmented. Earthworms can regrow broken off segments of their bodies.... So the answer is [(D)]

Most ecosystems need what?
Options:
- (A) invasive species
- (B) water
- (C) insects
- (D) food
- (E) tornadoes
- (F) recycling
- (G) plants
- (H) scientists
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Let's think first: Most ecosystems get energy from sunlight. Sunlight is turned into energy by plants. Most ecosystems need plants.... So the answer is [(G)]

Which is higher on the food chain?
Options:
- (A) insects
- (B) animals
- (C) humans
- (D) glucose
- (E) decomposers
- (F) herbivores
- (G) producers
- (H) consumers
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Let's think first: Consumers take in food by eating producers or other living things. Decomposers produce nutrients for producers. Decomposers make nutrients for organisms that become food for consumers.... So the answer is [(H)]

What enables natural selection to occur?
Options:
- (A) environment
- (B) mutations
- (C) competition
- (D) relocation
- (E) Darwin
- (F) evolutionary development
- (G) root growth
- (H) research
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Let's think first: Mutations are essential for evolution to occur. Natural selection is the mechanism of evolution. Mutations allow for natural selection to occur.... So the answer is [(B)]