Ecosystem Chapter-Wise Test 22

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which of the following is a correct statement about food webs?

Food webs consist of multiple interconnected food chains
Food webs exclude decomposers
Food webs do not show energy transfer
Food webs destabilize ecosystems
1

Food webs are formed by multiple interconnected food chains and illustrate complex feeding relationships in an ecosystem.

Which of the following statements about nutrient cycling is incorrect?

It helps in the continuous use of nutrients
It involves both biotic and abiotic components
It is a unidirectional process
It includes gaseous and sedimentary cycles
3

Nutrient cycling is a cyclic process, not unidirectional, ensuring the continuous reuse of essential nutrients in an ecosystem.

Which of the following statements about food webs is incorrect?

Food webs consist of multiple interconnected food chains
Food webs exclude decomposers
Food webs show complex feeding relationships
Food webs help maintain ecosystem stability
2

Food webs include decomposers, which play a crucial role in nutrient cycling and ecosystem balance.

Which organism is an example of a secondary consumer?

Grass
Deer
Lion
Frog
4

A frog is a secondary consumer as it feeds on primary consumers like insects.

Why is the pyramid of energy always upright?

Energy is fully transferred between trophic levels
Energy is lost as heat at each level
Consumers store more energy than producers
Energy cycles continuously between trophic levels
2

The pyramid of energy is always upright because energy is lost as heat at each trophic level, making energy transfer inefficient.

In an aquatic ecosystem, the major producers are:

Zooplankton
Phytoplankton
Mollusks
Small fish
2

Phytoplankton are the primary producers in aquatic ecosystems, converting sunlight into energy through photosynthesis.

Which of the following correctly defines net primary productivity (NPP)?

Total energy captured by plants
Energy available to consumers after respiration
Total energy lost as heat in an ecosystem
Energy used by decomposers
2

Net Primary Productivity (NPP) is the energy available to consumers after subtracting respiration losses from Gross Primary Productivity (GPP).

Which of the following is NOT a function of decomposers?

Breaking down dead organic matter
Releasing nutrients into the ecosystem
Producing their own food through photosynthesis
Converting organic substances into inorganic nutrients
3

Decomposers do not perform photosynthesis; they break down dead organic matter and recycle nutrients.

Which of the following statements about the nitrogen cycle is incorrect?

Denitrification releases nitrogen gas back into the atmosphere
Plants can absorb nitrogen gas directly from the atmosphere
Nitrogen fixation converts atmospheric nitrogen into usable forms
Decomposers help release nitrogen from organic matter
2

Plants cannot absorb nitrogen gas directly from the atmosphere; they depend on nitrogen-fixing bacteria.

Which of the following statements about food webs is incorrect?

Food webs consist of multiple interconnected food chains
Food webs exclude decomposers
Food webs provide ecosystem stability
Food webs illustrate the complex feeding relationships in an ecosystem
2

Food webs include decomposers, which play a crucial role in recycling nutrients.

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