Ecosystem Chapter-Wise Test 18

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which of the following statements about food chains is incorrect?

Energy flow in food chains is unidirectional
Food chains always start with producers
Food chains do not include decomposers
Each trophic level has less energy than the previous one
3

Decomposers can be part of food chains, especially in the detritus food chain.

Which of the following best describes the pyramid of biomass in a forest ecosystem?

Always upright
Always inverted
Unstable
Constantly changing
1

In a forest ecosystem, the pyramid of biomass is always upright because the biomass of producers is greater than that of consumers.

Which ecosystem type has the highest net primary productivity per unit area?

Desert
Tundra
Tropical rainforest
Deep ocean
3

Tropical rainforests have the highest net primary productivity per unit area due to abundant sunlight, water, and nutrient availability.

Which of the following statements about the pyramid of energy is incorrect?

The pyramid of energy is always upright
Energy is lost as heat at each trophic level
Primary consumers receive more energy than producers
Energy transfer is inefficient between trophic levels
3

Primary consumers receive less energy than producers because energy is lost as heat at each trophic level.

Which of the following factors does NOT directly affect primary productivity?

Sunlight availability
Nutrient availability
Temperature
Decomposer activity
4

Primary productivity is affected by sunlight, nutrient availability, and temperature, but decomposer activity mainly influences decomposition.

Which of the following best explains why energy transfer between trophic levels is inefficient?

All energy is transferred to the next trophic level
Most energy is lost as heat during metabolic activities
Higher trophic levels store more energy
Producers do not store energy
2

Energy transfer is inefficient because most energy is lost as heat due to metabolic activities, limiting the amount transferred to the next level.

Which of the following is NOT a step in the decomposition process?

Leaching
Fragmentation
Photosynthesis
Mineralization
3

Photosynthesis is a process performed by autotrophs, whereas decomposition includes leaching, fragmentation, humification, and mineralization.

Why is the pyramid of energy always upright?

Energy increases at higher trophic levels
Energy is lost as heat at each trophic level
Consumers store more energy than producers
Energy is continuously recycled
2

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

Which of the following statements about energy flow in an ecosystem is incorrect?

Energy flow is unidirectional
Energy is lost as heat at each trophic level
All energy is transferred between trophic levels without loss
Producers capture solar energy for photosynthesis
3

Not all energy is transferred between trophic levels; most is lost as heat during metabolic processes.

Which of the following statements about grazing food chains is incorrect?

They begin with living producers
Herbivores are the first consumers
Energy transfer is always 100% efficient
They transfer energy from plants to higher trophic levels
3

Energy transfer is not 100% efficient; only about 10% of energy is passed on to the next trophic level.

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