MCQ 11 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : A food chain can have a maximum of three trophic levels.
Reason : Energy available at each trophic level keeps on decreasing as we move higher up the food chain.
- A
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- ✓
$A$ is false, but $R$ is true.
AnswerCorrect option: D. $A$ is false, but $R$ is true.
A food chain can have a maximum of five to six trophic levels, this is because a lot of energy is lost as heat at each trophic level on account of metabolism. So, a small amount of energy becomes available to the next trophic level. This limits the number of trophic level in a food chain.
View full question & answer→MCQ 21 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Plastic, glass and metal wastes keep accumulating in our surrounding and their amount never reduces with time.
Reason : Plastic, glass and metal wastes are non $-$ biodegradable, and they cannot be decomposed by microorganisms.
- ✓
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: A. Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
The waste material which cannot be broken down into non $-$ poisonous or harmless substances in nature are called non $-$ biodegradable wastes. This is because decomposer microbes cannot act upon them, e.g., plastic, glass and metal objects.
View full question & answer→MCQ 31 Mark
In the following questions, a statement of Assertion is given by the corresponding statement of Reason. Of the statements, mark the correct answer as
Assertion : Light is the primary source of energy in nearly all ecosystems.
Reason : Light is used by autotrophs to synthesise their food.
- ✓
If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
- B
If both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
- C
If Assertion is true, but Reason is false.
- D
If Assertion is false, but Reason is true.
AnswerCorrect option: A. If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
Light energy $($sunlight$)$ is the primary source of energy in nearly all ecosystems.
An autotroph is an organism that can produce its own food using light, water, carbon dioxide, or other chemicals. Because autotrophs produce their own food, they are sometimes called producers. Some types of bacteria are autotrophs. Most autotrophs use a process called photosynthesis to make their food.
View full question & answer→MCQ 41 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : $\text{DDT}$ can pass along food chain from crops to man or other animals and harm them.
Reason : $\text{DDT}$ is non $-$ biodegradable and cannot be metabolized within bodies of living organisms and accumulates in their bodies.
- ✓
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: A. Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
View full question & answer→MCQ 51 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Hospital wastes like used syringes, urine bags, etc. can be incinerated.
Reason : Incineration burns the waste at very high temperature and converts it to ashes.
- ✓
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: A. Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
Hospital waste contains a lot of germs, so it should not be disposed openly. Burning the waste kills the germs and disposes the waste in proper way.
View full question & answer→MCQ 61 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : If pesticide is present in water bodies, then fish eating birds accumulate maximum amount of $\ce{DDT}$ in their bodies.
Reason : Pesticides are not metabolized within bodies of living organisms and get concentrated at each trophic level, leading to bioaccumulation.
- ✓
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: A. Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
View full question & answer→MCQ 71 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Ozone is a very important layer of atmosphere.
Reason : Ozone protects the living organisms from harmful $UV$ radiations of sun.
- ✓
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: A. Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
View full question & answer→MCQ 81 Mark
In the following questions, a statement of Assertion is given by the corresponding statement of Reason. Of the statements, mark the correct answer as
Assertion : Biotic components of an ecosystem include all the living organisms present in that ecosystem.
Reason : Biotic components also include wind, gases, light, etc.
- A
If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
- B
If both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
- ✓
If Assertion is true, but Reason is false.
- D
If Assertion is false, but Reason is true.
AnswerCorrect option: C. If Assertion is true, but Reason is false.
On the other hand, biotic factors include living components of the ecosystem. The examples of the abiotic factors are sunlight, the wind, clouds, water, rocks, energy, temperature, soil, etc. while the examples of biotic factors are plants and trees, animals, microorganisms such as fungi, bacteria, algae.
View full question & answer→MCQ 91 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Recycling is the way of managing plastic waste.
Reason : Broken plastic articles are sent to plastic processing units, where they are melted and remolded to make new plastic art ides.
- A
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- ✓
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: B. Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
Plastics are non $-$ biodegradable. They cannot be decomposed by the action of microbes. Recycling them can manage them effectively.
View full question & answer→MCQ 101 Mark
For two statements are given $- $ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Paper cups are better option than plastic cups for serving tea.
Reason : Paper cups are biodegradable and can even be disposed of by burning.
- ✓
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: A. Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
View full question & answer→MCQ 111 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Food waste can be converted to compost by burying in a pit dug into ground and used as manure.
Reason : Non $-$ biodegradable wastes like fruit and vegetable peels, tea leaves, broken glass jar are ideal for composting.
- A
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- ✓
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: C. $A$ is true, but $R$ is false.
Biodegradable domestic waste such as left over food, fruit and vegetables peels, leaves of potted plants can be converted in to compost.
View full question & answer→MCQ 121 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Using jute bags while shopping is more environment friendly as compared to polythene bags.
Reason : Jute is biodegradable, whereas polythene bag is non $-$ biodegradable.
- ✓
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: A. Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
Jute bags can be reused repeatedly for shopping and get decomposed when discarded. Poly bags on the other hand keep on accumulating as solid waste and harm our environment. They can clog drainage, pollute river bodies and are extremely dangerous to grazing animals who chew them mistakenly. So, jute bags are more environment friendly than poly bags.
View full question & answer→MCQ 131 Mark
In the following questions, a statement of Assertion is given by the corresponding statement of Reason. Of the statements, mark the correct answer as
Assertion : Ozone layer shields the surface of Earth from $UV$ radiations.
Reason : The $UV$ radiations are highly damaging to organisms.
- ✓
If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
- B
If both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
- C
If Assertion is true, but Reason is false.
- D
If Assertion is false, but Reason is true.
AnswerCorrect option: A. If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
They help shield our planet from harmful solar radiation. The ozone layer, in the stratosphere, is where about $90\%$ of the ozone in the Earth system is found. The ozone layer in the stratosphere shields life on Earth from most $UV-B$ and $UV - C,$ the most harmful varieties of ultraviolet radiation.
View full question & answer→MCQ 141 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Gases used in cooling devices can lead to depletion of ozone layer of atmosphere.
Reason : Carbon monoxide which is widely used as coolant in refrigerator reacts with ozone and destroys it.
- A
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- ✓
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: C. $A$ is true, but $R$ is false.
Chlorofluorocarbon which is widely used as coolant in refrigerator reacts with ozone and destroys it.
View full question & answer→MCQ 151 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Ozone depletion can be reduced by limiting the use of air conditioners and refrigerators.
Reason : Air conditioner and refrigerators release chlorofluorocarbons in the atmosphere that destroy ozone.
- ✓
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: A. Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
View full question & answer→MCQ 161 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : An ecosystem consists of a living biological community and its non $-$ living environment.
Reason : Ecosystem functions as self $-$ sufficient or independent unit in nature.
- A
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- ✓
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: B. Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
View full question & answer→MCQ 171 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : The energy available to deer in a food chain is more as compared to that available to lion.
Reason : Deer occupies second trophic level whereas lion occupies first trophic level in a food chain operating in grassland ecosystem.
- A
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- ✓
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: C. $A$ is true, but $R$ is false.
Deer occupies second trophic level in a food chain as it is primary consumer and directly feeds on plants. Lion occupies higher trophic level as it is a top carnivore and acts as secondary or tertiary consumers. Energy available to deer will be higher as compared to lion, as energy keeps on decreasing from one trophic level to another due to loss as heat.
View full question & answer→MCQ 181 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : A food chain comprises of producers and consumers.
Reason : Consumers can be herbivores, carnivores and omnivores.
- A
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- ✓
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: B. Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
A food chain always starts with producers or green plants who synthesize food. All consumers depend on green plants for food and energy, directly or indirectly.
View full question & answer→MCQ 191 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : The flow of energy in a food chain operating in an ecosystem is always unidirectional.
Reason : Lots of energy is lost as heat from living organisms at each trophic level of a food chain.
- A
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- ✓
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: B. Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
View full question & answer→MCQ 201 Mark
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Decomposers help in recycling of nutrients between living and non $-$ living components of ecosystem.
Reason : Decomposers help in decomposing dead bodies of organisms and return various nutrient elements to their source viz soil, water and air.
- ✓
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
- B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
- C
$A$ is true, but $R$ is false.
- D
$A$ is false, but $R$ is true.
AnswerCorrect option: A. Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
View full question & answer→