Explanation

• A hydrometer is an instrument used to measure the specific gravity of liquids.
• It works based on the principle of buoyancy.
• It is widely used to test milk, alcohol, and battery acid.
• Commonly used in laboratories and industries.

Last verified on 30-01-2026

Explanation

• Urea fertilizer contains 46% nitrogen (N).
• Urea is a white crystalline solid.
• It is widely used as a fertilizer and animal feed additive.

Last verified on 31-01-2026

Explanation

• Apiculture is the practice of rearing honeybees for honey and wax production.
• Helps in pollination and increasing crop yields.
• Honey, beeswax, and propolis are valuable products from apiculture.

• Sericulture → Rearing of silk worms.
• Silviculture → Cultivation of trees and forests.

Last verified on 30-01-2026

Explanation

• The study of tissues is called Histology.
• It involves examining the structure, composition, and function of cells and tissues under a microscope.
  

Additional information:

• Geology is the study of rocks and Earth's structure.
• Radiology is the study of medical imaging techniques like X-rays and MRI.

Last verified on 22-01-2026

Explanation

A species that no longer lives anywhere on the earth is called extinct.

This term refers to a species that has no living individuals remaining on the planet, often determined when the last surviving member dies. 

Examples: Well-known examples include the dinosaur, the woolly mammoth, and the passenger pigeon.

Explanation

The ripening of fruits is a biochemical process.

Oxygen is essential for cellular respiration, which drives ripening.

It helps in conversion of starches to sugars and softening of fruit tissue.

Controlled oxygen levels are used in storage and packaging to manage ripening.

Explanation

Anthracite is the highest grade of coal with the highest carbon content.

It has low moisture and impurities, making it very efficient as fuel.

It burns cleanly and produces more heat compared to other types of coal.

Other forms like lignite and bituminous have higher moisture and lower carbon.

Explanation

Sucrose is a common disaccharide found in sugarcane and sugar beet.

It is formed by linking one glucose molecule and one fructose molecule.

The bond between them is a glycosidic linkage.

Disaccharides are broken down into monosaccharides during digestion.

Explanation

In chloroplasts, the Calvin cycle occurs in the stroma.

CO₂ is fixed and converted into sugars in this area.

Thylakoids are the site of light-dependent reactions, not sugar formation.

Stroma contains enzymes needed for carbon fixation.

Explanation

Scientists estimate that 33% of the Earth’s area should be conserved.

This helps maintain biodiversity and ecological balance.

Protected areas include forests, wetlands, and marine zones.