GED Science Practice Test: Genetics, Evolution and Ecosystems
- Life Science: Genetics, Evolution and Ecosystems
- 10 questions
- 13 minutes
These 10 questions cover heredity, evolution and ecology on the GED Science test, including Punnett squares, energy in food chains and reading population data. For genetics questions, sketch a quick Punnett square instead of guessing the ratio.
Tap an option to mark your answer. You can change your mind, or tap the same option again to leave the question blank. The correct answers and explanations appear when you finish the test.Tap an option to answer; tap it again to leave the question blank.
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Question 1
In a type of rabbit, the allele for brown fur (B) is dominant over the allele for white fur (b). Two rabbits with the genotype Bb are crossed.
What is the probability that an offspring will have white fur?
Correct answer: B
The Punnett square for Bb × Bb gives BB, Bb, Bb and bb. Only bb has white fur, so the chance is 1 in 4, or 25%. The choice 75% is the chance of brown fur.
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Question 2
In pea plants, the allele for purple flowers (P) is dominant over the allele for white flowers (p). A plant with genotype Pp is crossed with a plant with genotype pp.
What percent of the offspring are expected to have purple flowers?
Correct answer: D
The cross Pp × pp gives Pp, Pp, pp and pp. Half of the offspring carry a P allele and have purple flowers. The 75% choice is the result of a Pp × Pp cross.
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Question 3
Which statement best describes a gene?
Correct answer: A
A gene is a section of DNA whose sequence codes for a protein or another product the cell needs. The structure that releases energy from food is the mitochondrion, not a gene.
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Question 4
A human skin cell contains 46 chromosomes.
How many chromosomes does a normal human egg cell contain?
Correct answer: C
Egg and sperm cells form by meiosis, which halves the chromosome number to 23. When an egg and a sperm join, the fertilized egg has 46 again. The choice 46 is the number in body cells made by mitosis.
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Question 5
A population of beetles lives on tree bark. After nearby factories cover the bark with dark soot, birds find light-colored beetles more easily than dark ones. Over many generations, most beetles in the population become dark.
Which statement best explains this change?
Correct answer: B
This is natural selection: a trait that helps individuals survive is passed on more often, so it becomes common over generations. Individual beetles cannot change their inherited color on purpose.
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Question 6
In an ecosystem, producers capture 10,000 kilocalories of energy. On average, about 10% of the energy at one level of a food chain is passed to the next level.
About how much of this energy reaches the tertiary consumers?
Correct answer: C
The energy passes three times: producers to primary consumers (1,000), to secondary consumers (100), to tertiary consumers (10 kilocalories). The choice 100 stops one step early, at the secondary consumers.
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Question 7
Bees drink nectar from flowers. While they feed, they carry pollen from flower to flower, which helps the plants reproduce.
What type of relationship do bees and flowering plants have?
Correct answer: A
Both species benefit: the bee gets food and the plant gets pollinated, which is mutualism. In commensalism only one species benefits while the other is not affected.
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Question 8
A snake species that eats birds is accidentally brought to an island. The island's native birds have never lived with this kind of predator.
What is the most likely short-term effect on the native bird populations?
Correct answer: D
Prey that has never faced a predator usually lacks behaviors that protect it, so a newly introduced predator can reduce its numbers quickly. Flying does not protect eggs and chicks in nests.
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Question 9
The table shows the size of a deer population in a protected forest.
Year 0 1 2 3 4 5 6 Deer 50 120 260 420 490 500 498 What is the best estimate of the forest's carrying capacity for deer?
Correct answer: C
Carrying capacity is the largest population the environment can support over time. The population grows quickly at first and then levels off at about 500 deer. The choice 260 is a point during the fast-growth stage, not the limit.
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Question 10
Which pair of substances do plants take in and use as raw materials for photosynthesis?
Correct answer: B
Photosynthesis uses light energy to turn carbon dioxide and water into glucose and oxygen. Oxygen and glucose are the products of photosynthesis, not its raw materials.
Questions you leave blank are not counted as wrong.
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