Q18
3 marksShort AnswerSection B

(a) From the following group of organisms create a food chain which is the most advantageous for Human beings in terms of energy.

(b) State the possible disadvantage if the cereal plant is growing in soil rich in pesticides.

(c) Construct a food web using the organisms mentioned above.


OR


(a) Write two harmful effects of using plastic bags on the environment. Suggest alternatives to the usage of plastic bags.

(b) List any two practices that can be followed to dispose off the waste produced in our homes.

Figure for question 18
Our Environment
Ecosystem
Official Answer

(a) The most advantageous food chain for human beings in terms of energy would be: Cereal plant →\rightarrow Human beings. This is because cereal plants are primary producers that convert sunlight into chemical energy through photosynthesis, and humans can directly consume them as a source of energy. (b) If the cereal plant is growing in soil rich in pesticides, it may absorb these harmful chemicals, which can then be transferred to humans who consume the plant. This can lead to health problems and even long-term damage to the human body. (c) A food web using the organisms mentioned above could be: Cereal plant →\rightarrow Insect →\rightarrow Frog →\rightarrow Snake →\rightarrow Human beings. This food web shows the interconnectedness of different species in an ecosystem and how energy is transferred from one species to another.

food chainecosystemprimary producerspesticidesfood web

Marking Scheme

  • 1(a) 1 mark for identifying the most advantageous food chain
  • 2(b) 1 mark for explaining the possible disadvantage of pesticides in the soil
  • 3(c) 1 mark for constructing a correct food web

Hint

To answer this question, think about the flow of energy in an ecosystem and how it is transferred from one species to another. Consider the role of primary producers like cereal plants and how they are consumed by other species. Also, think about the potential harm caused by pesticides in the soil and how they can be transferred to humans through the food chain.

Quick Oral Answer

The most advantageous food chain for human beings in terms of energy is the one that involves the direct consumption of cereal plants. This is because cereal plants are primary producers that convert sunlight into chemical energy through photosynthesis, making them the most direct source of energy for humans. However, if the cereal plant is growing in soil rich in pesticides, it may absorb these harmful chemicals, which can then be transferred to humans who consume the plant. This can lead to health problems and even long-term damage to the human body. A food web using the organisms mentioned above could be: Cereal plant →\rightarrow Insect →\rightarrow Frog →\rightarrow Snake →\rightarrow Human beings. This food web shows the interconnectedness of different species in an ecosystem and how energy is transferred from one species to another.

Analysis & Explanation

This question requires the application of knowledge about ecosystems and food chains. The correct answer is based on the understanding that cereal plants are primary producers that convert sunlight into chemical energy through photosynthesis, making them the most direct source of energy for humans. The question also requires the consideration of the potential harm caused by pesticides in the soil, which can be transferred to humans through the food chain. The construction of a food web using the organisms mentioned above demonstrates the interconnectedness of different species in an ecosystem and how energy is transferred from one species to another.

Common Mistakes

  1. 1assuming that the most advantageous food chain is the one with the most species
  2. 2not considering the potential harm caused by pesticides in the soil
  3. 3not constructing a correct food web

Interesting Facts

Cereal plants are a major source of energy for humans

Pesticides can have harmful effects on human health

Food webs show the interconnectedness of different species in an ecosystem

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2020?

This question carries 3 marks in the CBSE Class 10 Science 2020 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Our Environment" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Ecosystem" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2020 paper?

This is a Short Answer question from Section B in the CBSE Class 10 Science 2020 paper.