,BIOD 102 Module 6 | Q&A | 2026/2027 | Essential Biology | Portage
Learning
1. Which of the following is the broadest level of ecological organization?
A) Community
B) Ecosystem
C) Biome
D) Biosphere
Correct Answer: Biosphere
Rationale: The biosphere is the broadest level of ecological organization,
encompassing all ecosystems on Earth. The correct hierarchy from smallest
to largest is organism → population → community → ecosystem → biome →
biosphere.
2. In an ecosystem, which of the following is considered an abiotic factor?
A) Trees
B) Soil temperature
C) Bacteria
D) Fungi
Correct Answer: Soil temperature
Rationale: Abiotic factors are non-living components of an ecosystem, such
as temperature, water, sunlight, and soil composition. Trees, bacteria, and
fungi are all biotic (living) factors.
3. Which of the following organisms occupies the first trophic level in a food
chain?
,A) Primary consumers
B) Secondary consumers
C) Producers
D) Decomposers
Correct Answer: Producers
Rationale: Producers (autotrophs) occupy the first trophic level. They convert
solar energy into chemical energy through photosynthesis. Primary
consumers (herbivores) are at the second trophic level, and secondary
consumers are at the third.
4. Energy flow through an ecosystem is best described as:
A) Cyclical
B) Unidirectional
C) Reversible
D) Random
Correct Answer: Unidirectional
Rationale: Energy flows in one direction through an ecosystem—from
producers to consumers to decomposers. Unlike nutrients, which cycle,
energy is lost as heat at each trophic level and must be continually supplied
by the sun.
5. The carbon cycle involves the movement of carbon through which of the
following reservoirs? (Select all that apply)
A) Atmosphere
B) Oceans
, C) Fossil fuels
D) Living organisms
Correct Answer: Atmosphere; Oceans; Fossil fuels; Living organisms
Rationale: The carbon cycle moves carbon through all four reservoirs. Carbon
dioxide is exchanged between the atmosphere and oceans, organisms fix
carbon through photosynthesis, and fossil fuels store carbon over geological
timescales.
6. Which biome is characterized by permafrost, extreme cold, and low-
growing vegetation such as mosses and lichens?
A) Tundra
B) Coniferous forest
C) Temperate grassland
D) Tropical rainforest
Correct Answer: Tundra
Rationale: The tundra is a treeless biome characterized by permafrost
(permanently frozen subsoil), extreme cold, and low-growing vegetation.
Coniferous forests have evergreen trees, temperate grasslands have grasses,
and tropical rainforests have high rainfall and biodiversity.
7. Which of the following is a density-dependent factor that can limit
population growth?
A) Hurricane
B) Competition for food
C) Drought
Learning
1. Which of the following is the broadest level of ecological organization?
A) Community
B) Ecosystem
C) Biome
D) Biosphere
Correct Answer: Biosphere
Rationale: The biosphere is the broadest level of ecological organization,
encompassing all ecosystems on Earth. The correct hierarchy from smallest
to largest is organism → population → community → ecosystem → biome →
biosphere.
2. In an ecosystem, which of the following is considered an abiotic factor?
A) Trees
B) Soil temperature
C) Bacteria
D) Fungi
Correct Answer: Soil temperature
Rationale: Abiotic factors are non-living components of an ecosystem, such
as temperature, water, sunlight, and soil composition. Trees, bacteria, and
fungi are all biotic (living) factors.
3. Which of the following organisms occupies the first trophic level in a food
chain?
,A) Primary consumers
B) Secondary consumers
C) Producers
D) Decomposers
Correct Answer: Producers
Rationale: Producers (autotrophs) occupy the first trophic level. They convert
solar energy into chemical energy through photosynthesis. Primary
consumers (herbivores) are at the second trophic level, and secondary
consumers are at the third.
4. Energy flow through an ecosystem is best described as:
A) Cyclical
B) Unidirectional
C) Reversible
D) Random
Correct Answer: Unidirectional
Rationale: Energy flows in one direction through an ecosystem—from
producers to consumers to decomposers. Unlike nutrients, which cycle,
energy is lost as heat at each trophic level and must be continually supplied
by the sun.
5. The carbon cycle involves the movement of carbon through which of the
following reservoirs? (Select all that apply)
A) Atmosphere
B) Oceans
, C) Fossil fuels
D) Living organisms
Correct Answer: Atmosphere; Oceans; Fossil fuels; Living organisms
Rationale: The carbon cycle moves carbon through all four reservoirs. Carbon
dioxide is exchanged between the atmosphere and oceans, organisms fix
carbon through photosynthesis, and fossil fuels store carbon over geological
timescales.
6. Which biome is characterized by permafrost, extreme cold, and low-
growing vegetation such as mosses and lichens?
A) Tundra
B) Coniferous forest
C) Temperate grassland
D) Tropical rainforest
Correct Answer: Tundra
Rationale: The tundra is a treeless biome characterized by permafrost
(permanently frozen subsoil), extreme cold, and low-growing vegetation.
Coniferous forests have evergreen trees, temperate grasslands have grasses,
and tropical rainforests have high rainfall and biodiversity.
7. Which of the following is a density-dependent factor that can limit
population growth?
A) Hurricane
B) Competition for food
C) Drought
