Our Environment

Which of the following is a producer in a food chain?

1. aTiger
2. bGoat
3. cGreen plant
4. dEarthworm

The percentage of energy that is roughly transferred from one trophic level to the next in a food chain is:

1. a1%
2. b100%
3. c50%
4. d10%

Why do food chains usually have only 3-4 trophic levels?

1. aTop predators are large and need many prey
2. bAt each transfer only about 10 percent of energy is passed; very little energy remains beyond 4 levels to support a population
3. cDecomposers eat all the food before it reaches higher levels
4. dAll animals at the top eat plants directly

Which of the following is NOT a biodegradable substance?

1. aCow dung
2. bPlastic carry-bag
3. cCotton cloth
4. dVegetable peels

Which gas in the upper atmosphere protects Earth's surface from harmful UV radiation?

1. aCO2
2. bO2
3. cNitrogen
4. dOzone (O3)

If a food chain consists of grass -> grasshopper -> frog -> snake -> hawk and the producers (grass) capture 10000 J of solar energy, the energy approximately available to the hawk is:

1. a10000 J
2. b1000 J
3. c1 J
4. d100 J

Bacteria and fungi which decompose dead remains of plants and animals are called:

1. aProducers
2. bConsumers
3. cDecomposers
4. dTop consumers

Which of the following is the LEAST suitable disposal method for plastic waste?

1. aRecycling into new products
2. bOpen burning
3. cDisposal in dedicated landfills
4. dReduction at source by using cloth bags

Assertion (A): Food chains seldom have more than 4 trophic levels.

Reason (R): Energy transfer from one trophic level to the next is only about 10 percent; large losses occur as heat in respiration and life-activities at every level.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

Assertion (A): A vegetarian diet is more energy-efficient than a non-vegetarian diet.

Reason (R): Plants directly use solar energy via photosynthesis, while animals depend on plants or other animals; vegetarian food therefore involves only one transfer from producers, retaining more energy.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

Assertion (A): The concentration of pesticides like DDT increases up the food chain (biomagnification).

Reason (R): Non-biodegradable pesticides are not excreted easily and accumulate in fatty tissues; they pass up the food chain at higher and higher concentrations.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

Assertion (A): The use of CFCs led to depletion of the ozone layer.

Reason (R): Chlorofluorocarbons (CFCs) get broken down by ultraviolet light in the upper atmosphere; the chlorine atoms released catalytically destroy ozone molecules.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

1. I. A food chain shows the unidirectional flow of energy from producers through different trophic levels.
2. II. About 10 percent of the energy at one trophic level is transferred to the next trophic level.

Which of the above is/are correct?

1. aOnly I
2. bOnly II
3. cNeither I nor II
4. dBoth I and II

1. I. Producers (green plants) capture solar energy and convert it into chemical energy by photosynthesis.
2. II. Decomposers like bacteria and fungi break down dead organic matter, releasing simple substances back into the soil/atmosphere.
3. III. Producers depend on consumers for their nutrition.

Regarding components of an ecosystem, which of the above is/are correct?

1. aOnly II and III
2. bOnly I and II
3. cOnly I and III
4. dI, II and III

1. I. Substances which can be broken down by biological processes are called biodegradable.
2. II. Plastics, glass and DDT are examples of non-biodegradable substances.
3. III. All synthetic substances are automatically biodegradable.

Regarding biodegradable vs non-biodegradable, which of the above is/are correct?

1. aOnly I and III
2. bOnly II and III
3. cOnly I and II
4. dI, II and III

1. I. Biomagnification refers to the increasing concentration of certain non-biodegradable chemicals like pesticides in higher trophic levels of a food chain.
2. II. Humans, being at the top of many food chains, are particularly vulnerable to biomagnification of pesticides like DDT.
3. III. Biomagnification occurs because non-biodegradable chemicals are not excreted easily and accumulate in fatty tissues.

Regarding biomagnification, which of the above is/are correct?

1. aOnly I and II
2. bOnly II and III
3. cOnly I and III
4. dI, II and III

Match each organism with its trophic level:

1. a(i)-Q, (ii)-R, (iii)-S, (iv)-P
2. b(i)-P, (ii)-Q, (iii)-R, (iv)-S
3. c(i)-Q, (ii)-S, (iii)-P, (iv)-R
4. d(i)-R, (ii)-Q, (iii)-S, (iv)-P

Match each substance with its biodegradability:

1. a(i)-Q, (ii)-R, (iii)-P, (iv)-S
2. b(i)-P, (ii)-Q, (iii)-R, (iv)-S
3. c(i)-Q, (ii)-P, (iii)-R, (iv)-S
4. d(i)-R, (ii)-P, (iii)-Q, (iv)-S

Match each item in List I with its cause or effect in List II:

1. a(i)-Q, (ii)-S, (iii)-P, (iv)-R
2. b(i)-S, (ii)-Q, (iii)-P, (iv)-R
3. c(i)-Q, (ii)-S, (iii)-R, (iv)-P
4. d(i)-S, (ii)-Q, (iii)-R, (iv)-P

A village near a chemical industry reports increasing cancer cases. Lab tests show heavy metal contamination of the food and water. Which mechanism likely causes high concentrations to reach humans?

1. aThe metals decompose in soil
2. bThe metals self-degrade in two weeks
3. cThe metals only stay in air
4. dThe metals are absorbed by plants, then concentrate in animals; humans (top consumers) accumulate the highest dose via biomagnification

A village panchayat plans to manage solid waste produced by households. They collect: kitchen waste (vegetable peels, dung), plastic bags, broken glass, paper. Which of the following is the MOST environmentally sound strategy?

1. aBurn everything together in a single pit to save space
2. bBury all the waste in the village pond
3. cSegregate at source: compost the biodegradable kitchen waste, send plastic and paper for recycling, hand over glass for safe disposal/recycling
4. dSend all waste to the nearest city landfill without segregation

Why is the ozone layer essential for life on Earth, even though it does NOT itself provide oxygen for breathing?

1. aIt produces oxygen for the atmosphere
2. bIt absorbs the Sun's harmful UV radiation, protecting DNA and life from damage
3. cIt cools the Earth
4. dIt generates rainfall

An ecosystem comprises:

1. aOnly living organisms
2. bOnly non-living factors
3. cOnly producers and consumers
4. dBoth living (biotic) and non-living (abiotic) components interacting in an area

Which of the following is an example of a NATURAL ecosystem?

1. aA forest
2. bAn aquarium
3. cA garden
4. dAn agricultural field

Which group of organisms is NOT a CONSUMER?

1. aLions
2. bSparrows
3. cGreen plants
4. dFrogs

What is the role of decomposers in the ecosystem?

1. aThey break down dead organic matter and return nutrients to soil/atmosphere, closing the nutrient cycle
2. bThey produce energy directly from sunlight
3. cThey eat live animals
4. dThey control predator populations

From the passage, the ozone layer protects life by:

1. aProducing oxygen via photosynthesis
2. bAbsorbing harmful UV radiation from the Sun
3. cReflecting space radiation back into space
4. dFiltering microbes from the air

From the passage, which compounds were primarily responsible for the depletion of the ozone layer?

1. aCarbon dioxide and methane
2. bSulphur dioxide and nitrogen oxides
3. cOxygen and ozone itself
4. dChlorofluorocarbons (CFCs)

If CFCs continued to be released at the same rate as before the Montreal Protocol, the most LIKELY consequence over decades would be:

1. aSignificant thinning of the ozone layer leading to a sharp rise in skin cancers, cataracts, crop damage and disruption of marine food chains
2. bTotal destruction of all atmospheric oxygen
3. cSpontaneous formation of new ozone
4. dDoubling of stratospheric ozone

What does the international agreement called the 'Montreal Protocol' (mentioned in the passage) deal with?

1. aLimiting CO2 emissions to fight climate change
2. bReducing the production of plastics
3. cPhasing out the use of CFCs and other ozone-depleting substances
4. dBanning the use of pesticides