Explanation

• Black Gold: Petroleum (Crude Oil)
• Color: Dark black / brownish black
• Main Uses: Fuel, petrol, diesel, kerosene, plastics
• Importance: Backbone of modern industry and transport

Additional information:

• Top Oil-Producing Countries:
  1. Saudi Arabia
  2. USA
  3. Russia
  4. Iraq
  5. Iran

Last verified on 16-06-2026

Explanation

• The retina is the light-sensitive layer located at the back of the human eye.
• It contains special cells called rods and cones that detect light and color.
• These cells convert light into electrical signals.
• The signals are then sent to the brain through the optic nerve to produce vision.

Last verified on 11-03-2026

Explanation

• CFCs, carbon dioxide (CO₂), and methane (CH₄) are all greenhouse gases.
• Carbon dioxide traps heat in the atmosphere and increases temperature.
• Methane is a very strong greenhouse gas with high warming effect.
• CFCs also damage the ozone layer and act as greenhouse gases.

Last verified on 16-06-2026

Explanation

• Jaundice is a condition characterized by yellowing of the skin and eyes.
• It is caused by excess bilirubin due to liver dysfunction or disease.

Last verified on 01-04-2026

Explanation

• The part of the eye that controls the amount of light entering is the Iris.
• It adjusts the size of the pupil according to light intensity.
• In bright light, it reduces light entry; in dim light, it allows more light in.
• This process protects the retina and helps clear vision.

Last verified on 17-05-2026