Part 2 – Ecosystem Components: Abiotic & Biotic, Trophic Levels

Q1.

Which of the following is NOT an abiotic component of ecosystem?
a) Light
b) Temperature
c) Humidity
d) Bacteria

Answer: d) Bacteria

Explanation:

(a) Light → Abiotic.
(b) Temperature → Abiotic.
(c) Humidity → Abiotic.
(d) Correct → Bacteria = biotic component.

Q2.

Producers in an ecosystem are:
a) Autotrophs
b) Herbivores
c) Carnivores
d) Decomposers

Answer: a) Autotrophs

Explanation:

(a) Correct → Autotrophs (plants, algae) produce food.
(b) Herbivores = primary consumers.
(c) Carnivores = secondary/tertiary consumers.
(d) Decomposers recycle matter, not producers.

Q3.

The main producers in aquatic ecosystems are:
a) Phytoplankton
b) Zooplankton
c) Fish
d) Fungi

Answer: a) Phytoplankton

Explanation:

(a) Correct → Microscopic algae perform photosynthesis.
(b) Zooplankton = consumers.
(c) Fish = consumers.
(d) Fungi = decomposers.

Q4.

Primary consumers are always:
a) Carnivores
b) Herbivores
c) Omnivores
d) Decomposers

Answer: b) Herbivores

Explanation:

(a) Carnivores = secondary consumers.
(b) Correct → They feed on plants/producers.
(c) Omnivores eat both, not strictly primary.
(d) Decomposers are separate.

Q5.

Decomposers play a vital role because they:
a) Fix energy
b) Recycle nutrients
c) Act as primary producers
d) Store solar energy

Answer: b) Recycle nutrients

Explanation:

(a) Energy fixing done by producers.
(b) Correct → They mineralize organic matter back to soil.
(c) Not producers.
(d) No energy storage.

Q6.

Which of the following is a detritivore?
a) Earthworm
b) Deer
c) Tiger
d) Algae

Answer: a) Earthworm

Explanation:

(a) Correct → Earthworms feed on detritus.
(b) Deer = herbivore.
(c) Tiger = carnivore.
(d) Algae = producer.

Q7.

Secondary consumers are usually:
a) Herbivores
b) Carnivores
c) Producers
d) Decomposers

Answer: b) Carnivores

Explanation:
They feed on herbivores (primary consumers).

Q8.

In a grazing food chain, energy enters at:
a) Herbivore level
b) Carnivore level
c) Producer level
d) Decomposer level

Answer: c) Producer level

Explanation:
Solar energy → captured by producers → transferred upwards.

Q9.

Which of the following is an omnivore?
a) Cow
b) Human
c) Goat
d) Grasshopper

Answer: b) Human

Explanation:
Humans consume both plants and animals.

Q10.

In a terrestrial ecosystem, the major primary producers are:
a) Phytoplankton
b) Algae
c) Green plants
d) Fungi

Answer: c) Green plants

Explanation:
Plants capture sunlight and form food base.

Q11.

Which trophic level contains the largest biomass in a typical terrestrial ecosystem?
a) Producers
b) Primary consumers
c) Secondary consumers
d) Tertiary consumers

Answer: a) Producers

Explanation:
Energy base is broadest at producer level.

Q12.

The green plants and algae in an ecosystem form the:
a) First trophic level
b) Second trophic level
c) Third trophic level
d) Fourth trophic level

Answer: a) First trophic level

Explanation:

Producers = first trophic level.
Herbivores = second.
Carnivores = third/fourth.

Q13.

Primary consumers form which trophic level?
a) First
b) Second
c) Third
d) Fourth

Answer: b) Second

Explanation:
Herbivores feed on producers → second level.

Q14.

Top carnivores form which trophic level?
a) Second
b) Third
c) Fourth
d) Fifth

Answer: c) Fourth

Explanation:
Producers (1) → herbivores (2) → carnivores (3) → top carnivores (4).

Q15.

Which organism is NOT correctly matched with its role?
a) Grass – producer
b) Rabbit – primary consumer
c) Lion – secondary consumer
d) Earthworm – producer

Answer: d) Earthworm – producer

Explanation:
Earthworm is a detritivore, not a producer.

Q16.

Biotic components of an ecosystem include:
a) Producers
b) Consumers
c) Decomposers
d) All of the above

Answer: d) All of the above

Explanation:
All living organisms in an ecosystem = biotic components.

Q17.

Abiotic components of ecosystem include:
a) Sunlight
b) Water
c) Temperature
d) All of the above

Answer: d) All of the above

Explanation:
All physical factors of environment.

Q18.

Which ecosystem has phytoplankton as main producers?
a) Grassland
b) Forest
c) Lake
d) Desert

Answer: c) Lake

Explanation:
Aquatic → phytoplankton dominate.

Q19.

Fungi in an ecosystem act as:
a) Producers
b) Consumers
c) Decomposers
d) Primary consumers

Answer: c) Decomposers

Explanation:
Fungi break down organic matter.

Q20.

The biotic community of an ecosystem plus its abiotic environment forms a:
a) Population
b) Ecosystem
c) Biome
d) Biosphere

Answer: b) Ecosystem

Explanation:
Correct definition of ecosystem.

Q21.

A dog feeding on leftover food is acting as a:
a) Producer
b) Primary consumer
c) Scavenger
d) Decomposer

Answer: c) Scavenger

Explanation:
Scavengers consume dead/decaying organic matter.

Q22.

Herbivores are also called:
a) Producers
b) Primary consumers
c) Secondary consumers
d) Decomposers

Answer: b) Primary consumers

Explanation:
They feed directly on producers.

Q23.

Caterpillar feeding on a leaf belongs to which trophic level?
a) First
b) Second
c) Third
d) Fourth

Answer: b) Second

Explanation:
Leaf (producer) → caterpillar (primary consumer).

Q24.

Which of the following does NOT act as a producer?
a) Phytoplankton
b) Cyanobacteria
c) Green algae
d) Earthworm

Answer: d) Earthworm

Explanation:
Earthworm = detritivore, not a producer.

Q25.

Which forms the link between producers and higher trophic levels?
a) Primary consumers
b) Secondary consumers
c) Decomposers
d) Abiotic factors

Answer: a) Primary consumers

Explanation:
They transfer energy from producers to carnivores.

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Part 2 – Ecosystem Components: Abiotic & Biotic, Trophic Levels