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FALL ASSESSMENT:
ENVIRONMENTAL SCIENCE
2026/2027 QUESTIONS WITH
VERIFIED ANSWERS & COMPLETE
RATIONALES
## SECTION 1: ECOSYSTEMS & ECOLOGY
**1. Which of the following best describes an ecosystem?**
A. A community of organisms and their physical environment
interacting together
B. A group of organisms of the same species
C. All the populations in a given area
D. The biosphere
**Correct answer:** A community of organisms and their
physical environment interacting together
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**Rationale:** An ecosystem includes all living organisms (biotic
factors) in a given area, interacting with each other and with
their non-living environment (abiotic factors such as air, water,
soil, and sunlight). Like the autumn forest, everything is
interconnected.
---
**2. What is the primary source of energy for most
ecosystems?**
A. The moon
B. The sun
C. Geothermal heat
D. Decomposers
**Correct answer:** The sun
**Rationale:** The sun is the primary source of energy for most
ecosystems. Producers (plants, algae) convert sunlight into
chemical energy through photosynthesis, which is then passed
through the food chain. Like the autumn harvest, energy flows
from the sun to producers to consumers.
---
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**3. In a food chain, which organism is always at the first
trophic level?**
A. Primary consumer
B. Producer
C. Secondary consumer
D. Decomposer
**Correct answer:** Producer
**Rationale:** Producers (autotrophs) such as plants, algae,
and some bacteria occupy the first trophic level. They convert
sunlight into food energy. Primary consumers (herbivores) are
at the second level. Secondary consumers (carnivores) are at
the third level.
---
**4. What is the role of decomposers in an ecosystem?**
A. They produce food through photosynthesis
B. They break down dead organic matter and recycle nutrients
C. They consume primary producers
D. They regulate the population of predators
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**Correct answer:** They break down dead organic matter and
recycle nutrients
**Rationale:** Decomposers (bacteria, fungi) break down dead
organisms and waste, returning nutrients to the soil for use by
producers. They are essential for nutrient cycling. In autumn,
decomposers break down fallen leaves, enriching the soil.
---
**5. Which of the following is an example of a biotic factor in an
ecosystem?**
A. Temperature
B. Water
C. Predators
D. Soil pH
**Correct answer:** Predators
**Rationale:** Biotic factors are living components of an
ecosystem (predators, prey, competitors, parasites). Abiotic
factors are non-living components (temperature, water,
sunlight, soil, pH).
---
FALL ASSESSMENT:
ENVIRONMENTAL SCIENCE
2026/2027 QUESTIONS WITH
VERIFIED ANSWERS & COMPLETE
RATIONALES
## SECTION 1: ECOSYSTEMS & ECOLOGY
**1. Which of the following best describes an ecosystem?**
A. A community of organisms and their physical environment
interacting together
B. A group of organisms of the same species
C. All the populations in a given area
D. The biosphere
**Correct answer:** A community of organisms and their
physical environment interacting together
,2 | Page
**Rationale:** An ecosystem includes all living organisms (biotic
factors) in a given area, interacting with each other and with
their non-living environment (abiotic factors such as air, water,
soil, and sunlight). Like the autumn forest, everything is
interconnected.
---
**2. What is the primary source of energy for most
ecosystems?**
A. The moon
B. The sun
C. Geothermal heat
D. Decomposers
**Correct answer:** The sun
**Rationale:** The sun is the primary source of energy for most
ecosystems. Producers (plants, algae) convert sunlight into
chemical energy through photosynthesis, which is then passed
through the food chain. Like the autumn harvest, energy flows
from the sun to producers to consumers.
---
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**3. In a food chain, which organism is always at the first
trophic level?**
A. Primary consumer
B. Producer
C. Secondary consumer
D. Decomposer
**Correct answer:** Producer
**Rationale:** Producers (autotrophs) such as plants, algae,
and some bacteria occupy the first trophic level. They convert
sunlight into food energy. Primary consumers (herbivores) are
at the second level. Secondary consumers (carnivores) are at
the third level.
---
**4. What is the role of decomposers in an ecosystem?**
A. They produce food through photosynthesis
B. They break down dead organic matter and recycle nutrients
C. They consume primary producers
D. They regulate the population of predators
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**Correct answer:** They break down dead organic matter and
recycle nutrients
**Rationale:** Decomposers (bacteria, fungi) break down dead
organisms and waste, returning nutrients to the soil for use by
producers. They are essential for nutrient cycling. In autumn,
decomposers break down fallen leaves, enriching the soil.
---
**5. Which of the following is an example of a biotic factor in an
ecosystem?**
A. Temperature
B. Water
C. Predators
D. Soil pH
**Correct answer:** Predators
**Rationale:** Biotic factors are living components of an
ecosystem (predators, prey, competitors, parasites). Abiotic
factors are non-living components (temperature, water,
sunlight, soil, pH).
---
