Correct Answer: d) L waves

Explanation: Earthquake waves are categorized into body waves (P waves and S waves) and surface waves (R waves and L waves). Among these, surface waves are generally more destructive because they travel along the Earth’s surface and cause significant ground movement.

L waves, also known as Love waves, are a type of surface wave. They move the ground horizontally, causing intense shaking. This horizontal motion can lead to severe damage to buildings and infrastructure, especially near the epicenter where the energy is strongest.

– P waves (Primary waves) are the fastest and travel through solids, liquids, and gases, but they cause less damage as they primarily compress and expand the material.
– S waves (Secondary waves) are slower than P waves and only travel through solids. They cause more damage than P waves but are less destructive than surface waves.
– R waves (Rayleigh waves) are another type of surface wave that causes both vertical and horizontal ground motion, but L waves are typically more destructive due to their horizontal shearing effect.

Thus, L waves are the most destructive at the epicenter.

The correct answer is: d) 1, 2 and 3.

Explanation:

Coal combustion at thermal power plants releases several pollutants into the atmosphere. These include:

1. Carbon dioxide (CO2): Coal is a carbon-rich fuel, and when it burns, it releases a significant amount of carbon dioxide, a greenhouse gas that contributes to global warming.

2. Oxides of Nitrogen (NOx): During coal combustion, the high temperatures cause nitrogen in the air to react with oxygen, forming oxides of nitrogen. These are harmful pollutants that contribute to smog and acid rain.

3. Oxides of Sulphur (SOx): Coal often contains sulfur as an impurity. When coal is burned, the sulfur reacts with oxygen to form oxides of sulfur, such as sulfur dioxide (SO2). These are major contributors to acid rain and air pollution.

Since all three (carbon dioxide, oxides of nitrogen, and oxides of sulfur) are emissions from coal combustion at thermal power plants, the correct answer is d) 1, 2 and 3.

The correct answer is: Option B: Free energy is converted into potential energy and stored.

Explanation: Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy (free energy) from the sun into chemical energy (potential energy) stored in the form of glucose or other carbohydrates. During this process, carbon dioxide and water are used as raw materials, and oxygen is released as a byproduct. The light energy is captured by chlorophyll and other pigments in the chloroplasts, and it is used to drive the synthesis of glucose, which stores the energy in its chemical bonds. This stored energy can later be used by the plant or other organisms for various metabolic activities.

The correct answer is: Option B: 2 and 3 only.

Explanation:

Decomposers are organisms that break down dead organic matter into simpler substances, recycling nutrients back into the ecosystem. They play a crucial role in maintaining the balance of ecosystems by decomposing dead plants, animals, and other organic materials.

1. Virus: Viruses are not considered decomposers. They are non-living outside a host and cannot break down organic matter. Instead, they infect living organisms to replicate themselves. Hence, viruses do not perform the function of decomposition.

2. Fungi: Fungi are one of the primary decomposers in ecosystems. They break down complex organic materials like dead plants, wood, and animal remains into simpler compounds, which can then be absorbed by plants and other organisms.

3. Bacteria: Bacteria are also key decomposers. They decompose organic matter, especially in soil and water, by breaking it down into simpler substances, aiding in nutrient recycling.

Thus, only fungi and bacteria (2 and 3) are decomposers, while viruses are not.

Correct Answer: c) Water limits and fire

Explanation: In grasslands, trees do not replace grasses as part of ecological succession primarily due to two key factors: limited water availability and frequent fires. Grasslands typically exist in regions where water is insufficient to support the growth of large trees. Grasses are well-adapted to survive in such conditions because they require less water compared to trees.

Additionally, grasslands are often subject to periodic fires, which prevent the establishment and growth of trees. Grasses can quickly regenerate after fires due to their underground root systems, whereas trees are more vulnerable to fire damage. These factors together maintain the dominance of grasses in grassland ecosystems and prevent trees from taking over.

Correct Answer: Option B: Ecological niche

Explanation:

An ecological niche refers to the role and position an organism has in its environment. It includes not only the physical space (habitat) that the organism occupies but also its functional role in the ecosystem, such as its interactions with other organisms, its diet, its behavior, and how it contributes to the energy flow and nutrient cycles within the community.

– Ecotone (Option A) refers to a transitional area between two different ecosystems.
– Habitat (Option C) is the physical environment where an organism lives but does not encompass its functional role.
– Home range (Option D) refers to the area an animal uses for its daily activities, which is more about movement and territory rather than its ecological role.

The correct answer is: d) September Midday Sun overhead on Arctic Circle.

Explanation:

The position of the Sun at midday changes throughout the year due to the tilt of the Earth’s axis and its orbit around the Sun.

a) June – Midday Sun overhead at Tropic of Cancer: This is correct. Around June 21st (Summer Solstice in the Northern Hemisphere), the Sun is directly overhead at the Tropic of Cancer (23.5°N latitude).

b) December – Midday Sun overhead at Tropic of Capricorn: This is correct. Around December 21st (Winter Solstice in the Northern Hemisphere), the Sun is directly overhead at the Tropic of Capricorn (23.5°S latitude).

c) March – Midday Sun overhead on Equator: This is correct. Around March 21st (Spring Equinox), the Sun is directly overhead at the Equator.

d) September – Midday Sun overhead on Arctic Circle: This is incorrect. Around September 21st (Autumn Equinox), the Sun is directly overhead at the Equator, not the Arctic Circle. The Arctic Circle (66.5°N latitude) does not experience the Sun being directly overhead at any time of the year due to its position relative to the Earth’s tilt.

Thus, option d is not correctly matched.

The correct answer is: a) Asiatic Cheetah.

Explanation:

– The Asiatic Cheetah (Acinonyx jubatus venaticus) is considered extinct in the wild, with no confirmed sightings in its natural habitat for several years. It is critically endangered and categorized as extinct in the wild due to habitat loss and hunting pressures.

– In contrast, the other options listed are not extinct:

– Black Buck (Antilope cervicapra): This species is classified as endangered but is not extinct.

– Crocodile: Various species of crocodiles exist today, and they are not considered extinct. Some species are endangered, but they have not disappeared entirely.

– Indian Wild Ass (Equus hemionus): This species is also classified as endangered but remains extant.

Thus, among the choices provided, the Asiatic Cheetah stands out as the only example of an extinct species.

Correct Answer: Option C: 2, 1, 4, 3.

Explanation: 
1. Queensland: The capital city of Queensland is Brisbane. 
2. South Australia: The capital city of South Australia is Adelaide. 
3. Victoria: The capital city of Victoria is Melbourne.
4. Western Australia: Kalgoorlie is a city in Western Australia.

Now, let’s match the codes:
(a) Queensland – 2
(b) South Australia – 1
(c) Victoria – 4
(d) Western Australia – 3

The correct answer is: a) Laos

Explanation: A landlocked country is one that is entirely surrounded by land and does not have access to the sea. In Southeast Asia, Laos is the only landlocked country. It is bordered by China to the north, Vietnam to the east, Cambodia to the southeast, Thailand to the west, and Myanmar to the northwest. Unlike other countries in the region such as Thailand, Vietnam, and Cambodia, which have coastlines along seas or oceans, Laos has no direct access to any sea or ocean.