Q1. What is ‘estivation’?
(a) A state of deep hibernation during the winter months.
(b) A period of dormancy in animals to conserve energy and avoid extreme heat during the summer.
(c) The process of migrating to a different region for breeding and feeding.
(d) A method of camouflage used by certain insects to blend into their surroundings.
Ans: (b)
Explanation:
- Context: Estivation, also known as aestivation, is a biological phenomenon in which some animals enter a prolonged state of dormancy or inactivity during hot and dry conditions.
- It serves as a survival strategy to conserve energy and water. Animals undergoing estivation typically seek shelter in cool underground burrows, crevices, or cocoons, reducing their metabolic activity and energy consumption.
- This behaviour helps them avoid extreme dryness and the risk of predation.
- Examples of estivating animals include the West African lungfish, desert tortoises, and certain land snails.
Q2. Which of the following statements about microalgae is correct?
(a) Microalgae are a type of small aquatic animal.
(b) Microalgae are primarily found in terrestrial environments, such as forests and deserts.
(c) Microalgae are photosynthetic microorganisms and a source of renewable energy.
(d) Microalgae are commonly used in the production of beef and poultry.
Ans: (c)
Explanation:
- Context: A study published in the journal Nature Microbiology has revealed that microalgae, crucial in the ocean’s food chain and carbon capture, have developed a unique strategy to adapt to global warming and declining nutrient levels in the sea.
- As climate change reduces nutrient availability, these microalgae activate a protein called rhodopsin, similar to the protein in the human eye responsible for vision in dim light.
- This light-responsive protein enables microalgae to thrive by using sunlight as an alternative to traditional chlorophyll for growth.
- The study suggests that microbial rhodopsins are significant light capturers in the ocean, potentially absorbing as much light as chlorophyll-based photosynthesis.
- As global warming leads to nutrient scarcity at the ocean’s surface due to reduced mixing between the surface and deeper waters, microalgae struggle to produce food and capture carbon dioxide.
- This mechanism may have applications in biotechnology for enhancing the activity of light-dependent microbes for various purposes, from insulin production to biofuel.
Q3. Which of the following statements about the Amazon Rainforests is correct?
(a) The Amazon Rainforests are located in Southeast Asia.
(b) The Amazon Rainforests are primarily characterized by a cold, arid climate.
(c) The Amazon Rainforests are often referred to as the “lungs of the Earth.”
(d) The Amazon Rainforests cover approximately 25% of the world’s land area.
Ans: (c)
Explanation:
- The Amazon Rainforests are often referred to as the “lungs of the Earth” because they play a crucial role in producing oxygen and absorbing carbon dioxide, helping to regulate the Earth’s climate and oxygen levels. They are one of the planet’s most significant sources of oxygen.
About Amazon Rainforests:
- The Amazon Rainforests are vast, tropical forests in South America, covering 6,000,000 square km. They are found within 28 degrees north or south of the equator, receiving over 200 cm of rainfall annually. It plays a vital role in absorbing carbon dioxide and stabilizing the global climate and water cycle. Covering about 40% of Brazil, it’s bordered by the Guiana Highlands, the Andes, the Brazilian central plateau, and the Atlantic Ocean. The basin is shared by eight countries and French Guiana.
Q4. “Leaf litter decomposes faster than in any other biome and as a result the soil surface is often almost bare. Apart from trees, the vegetation is largely composed of plant forms that reach up into the canopy vicariously, by climbing the trees or growing as epiphytes, rooted on the upper branches of trees”. This is the most likely description of
(a) coniferous forest
(b) dry deciduous forest
(c) mangrove forest
(d) tropical rainforest
Ans: (d)
Explanation:
- Tropical rainforests are known for their rapid decomposition of leaf litter due to high temperatures and moisture, leading to nutrient cycling and quick recycling of organic matter. In rainforests, the soil surface is often almost bare because the leaf litter decomposes rapidly. Additionally, rainforests have a diverse plant community, including epiphytes and climbers, which grow on and up into the canopy, making them an excellent match for the description provided.
Q5. Under the Indian Constitution, concentration of wealth violates:
(a) the Right to Equality
(b) the Directive Principles of State Policy
(c) the Right to Freedom
(d) the Concept of Welfare
Ans: (b)
Explanation:
- Under the Indian Constitution, concentration of wealth violates the Directive Principles of State Policy.
- Article 39(c) of the Directive Principles of State Policy states that “the operation of the economic system does not result in the concentration of wealth and means of production to the common detriment”.
