Explanation

• The ideal depth for fish growth is around 100 fathoms.
• A fathom equals about 6 feet, so 100 fathoms ≈ 600 feet (≈180 meters).
• This zone has suitable light, temperature, and oxygen levels.
• It supports better food availability for marine life.

Last verified on 02-05-2026

Explanation

• Whales evolved from land-dwelling mammals.
• Their ancestors gradually adapted to aquatic life.
• Over millions of years, they moved from land to sea.
• They developed flippers instead of legs for swimming.
• This is an example of evolution and adaptation.

Last verified on 26-04-2026

Explanation

• Quinine is a medicine used to treat Malaria.
• It is obtained from the bark of the Cinchona tree.
• Native to South America (Andes region).
• One of the earliest effective treatments for malaria.

Last verified on 02-05-2026

Explanation

• Digestion begins in the mouth, starting immediately when food is ingested.
• Both mechanical digestion (chewing) and chemical digestion (salivary amylase breaking down carbohydrates) 

Additional information:

• Mouth: Food is chewed and mixed with saliva that contains enzymes to break down carbohydrates.
• Esophagus: Food is swallowed and passes through the esophagus into the stomach.
• Stomach: Food is mixed with stomach acid and enzymes to break down proteins and fats.
• Small Intestine: Nutrients are absorbed into the bloodstream.
• Large Intestine: Water and electrolytes are absorbed, and waste is eliminated.

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Last updated by NS on 01 MAY 2026

Explanation

• The stratosphere is heated mainly by ozone.
• Ozone layer absorbs harmful ultraviolet (UV) radiation from the Sun.
• This absorption converts solar energy into heat.
• It causes warming in the stratosphere instead of cooling.
• This layer protects Earth from dangerous UV rays.

Last verified on 01-05-2026