Explanation

• If the ozone layer disappears, harmful ultraviolet (UV) rays will reach the Earth's surface in much larger amounts.
• The ozone layer protects life by absorbing most of the Sun's harmful UV-B and UV-C radiation.
• Increased UV radiation can cause skin cancer, cataracts, and weakened immune systems.
• It can also damage crops, marine life, and ecosystems.
• The ozone layer is found mainly in the stratosphere.

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Explanation

• The Troposphere contains about 75% of the atmosphere's mass.
• It is the lowest layer of Earth's atmosphere.
• Altitude Range: About 8 km at poles to 15–18 km at equator.
• Main Gases: Nitrogen (78%), Oxygen (21%), and other gases.ev

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Explanation

• Chemical Formula: CH₃COOH (also written as C₂H₄O₂)
• IUPAC Name: Ethanoic Acid
• Type: Weak organic (carboxylic) acid
• Molar Mass: 60.05 g/mol
• Found in: Vinegar (about 4–8% acetic acid)

Last verified on 12-07-2026

Explanation

• In a nuclear reactor, energy is produced due to a controlled chain reaction.
• A controlled chain reaction releases energy steadily and safely.
• Control rods are used to regulate the number of neutrons and prevent excessive reactions.
• This controlled process is used to generate electricity in nuclear power plants.

Additional information:

• An uncontrolled chain reaction occurs in nuclear bombs.

Last verified on 11-07-2026

Explanation

• The chemical formula of ethyne is C₂H₂.
• Ethyne is the simplest alkyne.
• It is contains a triple bond between two carbon atoms.
• It is also commonly known as acetylene.
• It is a colorless, highly flammable gas.

Additional information:

• Methane → CH₄ (Alkane)
• Ethene → C₂H₄ (Alkene)
• Propene → C₃H₆
• Propyne → C₃H₄

Last verified on 11-07-2026

Explanation

• The primary purpose of microorganisms such as bacteria is to decompose dead organic matter and recycle nutrients.
• Bacteria break down dead plants, animals, and organic waste.
• This process returns nutrients to the soil, making them available for new life.
• Without decomposers, dead matter would accumulate, and nutrient cycling would stop.

Last verified on 11-07-2026

Explanation

• Stearic acid is a saturated fatty acid containing 18 carbon atoms (C18:0).
• It has no double bonds between carbon atoms, which makes it saturated.
• It is commonly found in animal fats and some vegetable fats.

Additional information:

• Palmitic acid – Saturated fatty acid (C16:0)
• Oleic acid – Unsaturated fatty acid (C18:1)
• Linoleic acid – Unsaturated fatty acid (C18:2)
• Linolenic acid – Unsaturated fatty acid (C18:3)

Last verified on 11-07-2026

Explanation

• Fish survival decreases due to the decomposition of organic matter.
• When organic matter increases, bacteria decompose it and consume dissolved oxygen.
• Low oxygen levels make it difficult for fish to breathe.
• This can lead to fish stress or even fish kills.
• Excess organic matter also reduces overall water quality.

Last verified on 11-07-2026

Explanation

• Geobacillus stearothermophilus is the standard biological indicator used to test the effectiveness of an autoclave.
• Its heat-resistant spores are difficult to kill, making them ideal for sterilization testing.
• If the spores are destroyed, the autoclave is functioning properly.
• It is widely used in hospitals, laboratories, and pharmaceutical industries.

Last verified on 11-07-2026

Explanation

• Extrusion is a manufacturing process in which metal is pressed through a shaped die under high pressure to produce the desired shape.
• It is used to manufacture products with a uniform cross-section.
• The process can be performed on hot or cold metal.
• Extrusion is widely used to produce rods, tubes, pipes, and structural sections.
• It provides a smooth surface finish and reduces material wastage.

Last verified on 10-07-2026