ASVAB ASVAB General Science Biology and Ecology — Questions and Answers

Question 1: Which type of symbiosis benefits one organism while the other is neither helped nor harmed?

Mutualism
Parasitism
Commensalism (Correct answer)
Competition

Correct answer: Commensalism

Commensalism is the relationship where one organism benefits and the other is unaffected.

Question 2: What is the primary role of decomposers in an ecosystem?

Produce oxygen through photosynthesis
Break down dead organic matter and recycle nutrients (Correct answer)
Convert nitrogen gas into ammonia
Transfer energy from producers to consumers

Correct answer: Break down dead organic matter and recycle nutrients

Decomposers like bacteria and fungi break down dead organisms, returning nutrients to the soil.

Question 3: Which organelle is responsible for producing ATP through cellular respiration?

Nucleus
Ribosome
Mitochondria (Correct answer)
Golgi apparatus

Correct answer: Mitochondria

Mitochondria are called the powerhouse of the cell because they generate ATP via cellular respiration.

Question 4: A population of rabbits grows rapidly with unlimited food. This best describes which type of population growth?

Logistic growth
Exponential growth (Correct answer)
Linear growth
Cyclical growth

Correct answer: Exponential growth

Exponential growth occurs when a population increases at a constant rate without resource limitations.

Question 5: What term describes the maximum population size an environment can sustainably support?

Population density
Biotic potential
Carrying capacity (Correct answer)
Ecological niche

Correct answer: Carrying capacity

Carrying capacity is the maximum number of individuals an environment can support given available resources.

Question 6: Which process moves water from the soil into a plant and eventually into the atmosphere?

Transpiration (Correct answer)
Precipitation
Condensation
Percolation

Correct answer: Transpiration

Transpiration is the evaporation of water from plant leaves, driving water uptake from the roots.

Question 7: Which blood cells are primarily responsible for fighting bacterial infections?

Red blood cells
Platelets
White blood cells (Correct answer)
Plasma cells

Correct answer: White blood cells

White blood cells (leukocytes) are the main immune cells that attack and destroy pathogens like bacteria.

Question 8: Which level of biological organization is ABOVE an organism but BELOW a community?

Biosphere
Ecosystem
Population (Correct answer)
Biome

Correct answer: Population

A population consists of individuals of the same species living in the same area, between the organism and community levels.

Question 9: What is the correct order of nitrogen fixation in the nitrogen cycle?

Atmosphere → soil bacteria → plants → animals (Correct answer)
Plants → animals → soil → atmosphere
Animals → plants → bacteria → atmosphere
Soil → atmosphere → plants → animals

Correct answer: Atmosphere → soil bacteria → plants → animals

Nitrogen-fixing bacteria convert atmospheric N₂ into ammonia in the soil, which plants then absorb.

Question 10: A scientist discovers a new organism that has a cell wall but no nucleus. What kingdom does it most likely belong to?

Fungi
Plantae
Monera (Bacteria) (Correct answer)
Protista

Correct answer: Monera (Bacteria)

Prokaryotes like bacteria have cell walls but lack a membrane-bound nucleus, placing them in kingdom Monera.

Question 11: Which of the following is an example of a biotic factor in an ecosystem?

Temperature
Soil pH
Predators (Correct answer)
Rainfall

Correct answer: Predators

Biotic factors are living components of an ecosystem, such as predators, prey, and plants.

Question 12: During meiosis, how does the chromosome number in daughter cells compare to the parent cell?

It stays the same
It doubles
It is halved (Correct answer)
It is quartered

Correct answer: It is halved

Meiosis reduces the chromosome number by half to produce haploid gametes (sperm and eggs).

Question 13: Which biome is characterized by permafrost, very low precipitation, and dominated by mosses and lichens?

Taiga
Tundra (Correct answer)
Desert
Temperate grassland

Correct answer: Tundra

The tundra biome has permanently frozen subsoil (permafrost), minimal precipitation, and sparse vegetation like mosses and lichens.

Question 14: What is the term for the variety of species living within a particular region or ecosystem?

Genetic diversity
Biodiversity (Correct answer)
Biomass
Abundance

Correct answer: Biodiversity

Biodiversity refers to the variety of species, genes, and ecosystems within a given area.

ASVAB ASVAB General Science Biology and Ecology

Which type of symbiosis benefits one organism while the other is neither helped nor harmed?

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