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Q.10. (a) What are human-made ecosystems? Give one example. (b) We do not clean a pond in the same manner as we do in an aquarium. Give reason to justify this statement. (c) List two advantages of using jute or cloth bags over polythene bags. SECTION D — Long Answer Question — Q. 11 × 4 Marks = 4 Marks Q.11. (a) Define an ecosystem. List two natural and two human-made ecosystems. (b) Draw a block diagram to show the flow of energy in an ecosystem. (c) The energy available to organisms at the second trophic level is 2000 J. Calculate the energy available at the fourth trophic level. SECTION E — Case / Situation Based Question — Q. 12 × 5 Marks = 5 Marks Q.12. Read the following passage and answer the questions that follow: The human body is made up of five important components, of which water is the main component. Food as well as potable water are essential for every human being. Food is obtained from plants through agriculture. Pesticides are being used extensively for a high yield in the fields. These pesticides are absorbed by plants from the soil along with water and minerals, and from water bodies these pesticides are taken up by aquatic animals and plants. As these chemicals are not biodegradable, they get accumulated progressively at each trophic level. The maximum concentration of these chemicals gets accumulated in our bodies and greatly affects the health of our mind and body. (i) Why is the maximum concentration of pesticides found in human beings? (1) (ii) Give one method which could reduce our intake of pesticides through food to some extent. (1) (iii) Various steps in a food chain represent: (1) (A) Food web (B) Trophic level (C) Ecosystem (D) Biomagnification (iv) With regard to various food chains operating in an ecosystem, man is a: (1) (A) Consumer (B) Producer (C) Producer and Consumer (D) Producer and Decomposer (v) Name the phenomenon by which non-biodegradable chemicals accumulate progressively at each trophic level. Write one harmful effect of this phenomenon on the ecosystem. (1) 3 NintyPlus — nintyplus.in NintyPlus Class X Science – Our Environment Chapter 13 — End of Question Paper 1 — NintyPlus — Helping You Score 90+ — nintyplus.in 4 NintyPlus — nintyplus.in NintyPlus Class X Science – Our Environment Chapter 13 NINTYPLUS Class X – Science (086) Chapter 13: Our Environment Mock Test Paper – 2 Time: 45 Minutes Maximum Marks: 25 Section: Roll No.: General Instructions: (i) All questions are compulsory. (ii) Marks for each question are indicated against it. (iii) Questions 1–6 are of 1 mark each (Section A: MCQ & Assertion–Reason). (iv) Questions 7–8 are of 2 marks each (Section B: Very Short Answer). (v) Questions 9–10 are of 3 marks each (Section C: Short Answer). (vi) Question 11 is of 4 marks (Section D: Long Answer). (vii) Question 12 is of 5 marks (Section E: Case-Based). (viii) Draw neat and labelled diagrams wherever required. SECTION A — Multiple Choice Questions — Q. 1–4 × 1 Mark each = 4 Marks Q.1. Identify the food chain in which the organisms of the second trophic level are missing: (A) Grass → Goat → Lion (B) Zooplankton → Phytoplankton → Small Fish → Large Fish (C) Tiger → Grass → Snake → Frog (D) Grasshopper → Grass → Snake → Frog → Eagle Q.2. What will happen if the deer are missing in the following food chain? Grass → Deer → Tiger (A) The population of tigers will increase. (B) The amount of grass will decrease. (C) The tigers will die. (D) The tigers will start eating grass.