Environmental Science

Coal-fired power plants produce a variety of emissions, with mercury being one of the key pollutants released. Mercury is a toxic substance that can accumulate in the environment and the food chain, posing significant health risks.

Step 1: Identify the emission.
Coal combustion leads to the emission of several pollutants, including mercury (Hg), which is released as a vapor during the burning of coal. Other substances like sulfur dioxide, carbon dioxide, and nitrogen oxides are also produced.

Step 2: Conclusion.
Therefore, coal-fired power plants emit mercury (Hg) as one of their major pollutants.

Final Answer: Mercury (Hg).

Step 1: Understanding a food chain.
A food chain is a linear sequence of organisms where each organism serves as a source of food for the next one in the chain. The energy is transferred from one organism to another as it moves through the food chain. In this question, we are asked to arrange organisms in the correct order based on their roles in the food chain.

Step 2: Identify the organisms and their roles.
Let's break down the organisms listed in the question:
- Grass: Grass is a primary producer, meaning it forms the base of the food chain. It produces energy through photosynthesis and provides food for herbivores.
- Grasshopper: A herbivore, the grasshopper feeds on grass and is considered a primary consumer.
- Frog: The frog is a secondary consumer because it feeds on grasshoppers, making it a carnivore in the food chain.
- Snake: The snake is a tertiary consumer as it feeds on frogs, making it a higher-level predator in the food chain.
- Eagle: The eagle is an apex predator, meaning it is at the top of the food chain. It feeds on snakes, and because it has no natural predators, it is the final link in this chain.

Step 3: Arranging the organisms.
To create a correct food chain, we start with the producers at the bottom and move up through the consumers. The correct order of organisms, starting from the base of the food chain and moving to the apex, is:
1. Grass (Producer)
2. Grasshopper (Primary consumer)
3. Frog (Secondary consumer)
4. Snake (Tertiary consumer)
5. Eagle (Apex predator) Thus, the correct order is: Grass → Grasshopper → Frog → Snake → Eagle. Final Answer: Grass → Grasshopper → Frog → Snake → Eagle.

Step 1: Understanding the chromosomes.
In humans, there are a total of 46 chromosomes in each cell, consisting of 22 pairs of autosomes (non-sex chromosomes) and 1 pair of sex chromosomes.

Step 2: The sex chromosomes.
The sex chromosomes are responsible for determining the biological sex of an individual. In males, the sex chromosomes are XY, and in females, they are XX.

Step 3: Conclusion.
Therefore, the number of sex chromosomes in every human cell is 1 pair.

Final Answer: 1 pair.

Step 1: Explanation of the options.
- (A) Recycle: Recycling plastic materials helps reduce waste by converting them into reusable materials, which is an effective way to reduce plastic pollution.
- (B) Reduce: Reducing the use of plastic is one of the most effective ways to minimize environmental damage caused by plastics.
- (C) Reuse: Reusing plastic items can help reduce the amount of plastic waste generated, which is beneficial for the environment.
- (D) Recover: While recovery refers to the process of collecting waste materials, it is not as effective as reducing, reusing, or recycling plastics to address the environmental impact.

Step 2: Conclusion.
Out of these options, "recover" is the least effective strategy for tackling plastic pollution compared to reducing, reusing, or recycling.

Final Answer: Recover.

Step 1: Understanding analogous organs.
Analogous organs are organs that perform the same function but are structurally different. They arise from different evolutionary origins.

Step 2: Explanation of options.
- (A) Forelimbs of a human and bird: These are homologous organs as they have a common evolutionary origin, despite serving different functions.
- (B) Wings of butterfly and bird: These are analogous organs. Both wings serve the purpose of flight, but they have different structures and evolutionary origins.
- (C) Heart of human and fish: These are homologous organs, not analogous, as they come from a common ancestor.
- (D) Leaves and tendrils of pea plant: These are modified structures and not analogous organs.

Step 3: Conclusion.
Therefore, the correct answer is wings of butterfly and bird, as they are analogous organs.

Final Answer: Wings of Butterfly and Bird.

Step 1: Understanding acid rain.
Acid rain is caused by the release of pollutants such as sulphur dioxide (SO2) and nitrogen oxides (NOx) into the atmosphere. These pollutants mix with water vapor, oxygen, and other chemicals in the atmosphere, leading to the formation of sulfuric and nitric acids.

Step 2: Explanation of options.
- (A) Emission of carbon dioxide from vehicles: While CO2 is a greenhouse gas, it does not contribute to acid rain.
- (B) Release of chlorofluorocarbons (CFCs): CFCs contribute to ozone depletion, not acid rain.
- (C) Combustion of fossil fuels, releasing sulphur dioxide, nitrogen oxides: This is the correct cause of acid rain. When fossil fuels are burned, they release sulphur dioxide and nitrogen oxides into the atmosphere, which combine with water to form acids.
- (D) Deforestation and land use changes: Deforestation can lead to environmental degradation but does not directly cause acid rain.

Step 3: Conclusion.
Therefore, the main cause of acid rain is the combustion of fossil fuels, which releases sulphur dioxide and nitrogen oxides.

Final Answer: Combustion of fossil fuels, releasing sulphur dioxide, nitrogen oxides.

Step 1: Understanding the Red Data Book.
The Red Data Book is a critical document published by the International Union for Conservation of Nature (IUCN). It provides comprehensive information about the conservation status of various species around the world. The book helps in identifying species that need protection and conservation efforts.

Step 2: Species categories listed in the Red Data Book.
The Red Data Book includes the following categories of species:
- Rare species: These are species that exist in very limited numbers. They are not yet endangered but are at risk of extinction if the current trends continue.
- Endangered species: These species are at high risk of extinction in the near future. They need immediate conservation efforts to prevent their extinction.
- Vulnerable species: These species are at risk of becoming endangered in the future, but they are not yet at the critical stage of endangerment. They require attention to prevent further decline.
- Fossils: Fossils are the remains of ancient species that no longer exist today. While they are important for understanding the history of life on Earth, they are not considered in the Red Data Book as they are not living species. Thus, the Red Data Book contains data on endangered and vulnerable species. Therefore, the correct answer is 3 & 4 are correct. Final Answer: 3 & 4 are correct.

Step 1: Characteristics of Eutrophic Lake.
An eutrophic lake is one that has high levels of nutrients, particularly nitrogen and phosphorus, which lead to high levels of algae and plant growth. These lakes typically have a lot of organic matter.

Step 2: Understanding the options.
- Incorrect. Eutrophic lakes have high nutrient levels, not low. - Incorrect. Eutrophic lakes are rich in organic matter due to excessive plant and algae growth. - Incorrect. Eutrophic lakes are highly productive due to abundant nutrients. - Correct. This is the defining characteristic of eutrophic lakes.

Step 3: Conclusion.
Eutrophic lakes are known for being rich in nutrients, which leads to high biological productivity.

Final Answer: Very rich in nutrients.

The contraction and expansion movement of the wall of the food pipe (esophagus) is called peristalsis. It helps in the movement of food from the mouth to the stomach. This is an involuntary movement controlled by smooth muscles in the digestive tract.

Step 1: Define peristalsis.
Peristalsis is a series of wave-like muscle contractions that move food along the digestive tract. It occurs in the esophagus, stomach, and intestines.

Step 2: Conclusion.
Thus, the contraction and expansion movement of the wall of the food pipe is called peristaltic movement.

Final Answer: Peristaltic movement.

The cell organelles that contain DNA are mitochondria and chloroplasts. These organelles have their own DNA, separate from the DNA found in the nucleus, which is the control center of the cell. Lysosomes, on the other hand, do not contain any DNA.

Step 1: Define the organelles.
- Mitochondria and Chloroplasts both contain DNA, which is essential for their function and replication. They have their own genetic material, which is why they are sometimes referred to as semi-autonomous organelles.
- Lysosomes are involved in cellular digestion but do not have any DNA, as they are membrane-bound vesicles that contain enzymes for breaking down waste materials.


Step 2: Conclusion.
Thus, the organelle that does not contain DNA is the lysosome.

Final Answer: Lysosome.

Step 1: Fat-soluble vitamins.
Fat-soluble vitamins are vitamins that dissolve in fat and are stored in the liver and fat tissues. The fat-soluble vitamins are:

Step 2: Vitamin C.
Vitamin C, also known as ascorbic acid, is a water-soluble vitamin, not a fat-soluble one. It dissolves in water and is not stored in the body.

Step 3: Conclusion.
Thus, the vitamin that is NOT fat-soluble is Vitamin C.

Final Answer: Vitamin C.