Our Environment

Topics in this chapter

• Ecosystem Components and Interactions
• Food Chains, Webs and Trophic Levels
• Energy Flow and Ten-Percent Law
• Nutrient Cycling and Ecological Balance
• Ozone Layer and UV Protection
• Waste, Pollution and Biomagnification

Cheat sheet

Practice questions

1. Question 1Q-0784EE

   Which of the following constitutes a food chain?

   1. A.Grass, wheat and mango
   2. B.Grass, goat and human
   3. C.Goat, cow and elephant
   4. D.Grass, fish and goat
   See the answer and solution
2. Question 2Q-282993

   The depletion of the ozone layer is a cause for concern because:

   1. A.It leads to global warming
   2. B.It allows harmful ultraviolet rays to reach the earth's surface
   3. C.It increases the concentration of oxygen in the atmosphere
   4. D.It causes frequent acid rain
   See the answer and solution
3. Question 3Q-7AA36D

   In a terrestrial ecosystem, the maximum energy is always available at which trophic level?

   1. A.Producers
   2. B.Herbivores
   3. C.Carnivores
   4. D.Top carnivores
   See the answer and solution
4. Question 4Q-6BD47C

   Which of the following groups contains only biodegradable items?

   1. A.Grass, flower and leather
   2. B.Grass, wood and plastic
   3. C.Fruit peels, cake and plastic bag
   4. D.Cake, wood and glass
   See the answer and solution
5. Question 5Q-740191

   Why do top carnivores in a food chain generally show the highest concentration of harmful pesticides like DDT, even when the initial concentration in water or soil is very low?

   1. A.Because they consume large amounts of water directly
   2. B.Due to biological magnification as non-biodegradable chemicals accumulate progressively along food chains
   3. C.Because they synthesize these chemicals inside their bodies during respiration
   4. D.Because their metabolic rate destroys helpful nutrients instead of toxins
   See the answer and solution