Explanation

• Nicolaus Copernicus proposed the heliocentric model.
• Heliocentric means the Sun is at the center.
• Earth and other planets revolve around the Sun.
• Proposed in the 16th century.
• Ptolemy supported the geocentric model (Earth-centered).

Explanation

• Nitrogen (N₂) → 78%

Additional information:

• Oxygen (O₂) → 21%
• Argon (Ar) → 0.93%
• Carbon dioxide (CO₂) → 0.04% (approximately)
• Other gases → Trace amounts

Last verified on 28-06-2026

Explanation

• Carbon dioxide (CO₂) — the main greenhouse gas causing global warming.

Additional information:

• Methane (CH₄) — potent, from livestock and fossil fuels.
• Nitrous oxide (N₂O) — from fertilizers and industry.
• Water vapor — natural, amplifies warming.
• Fluorinated gases — synthetic, very strong effect.

Explanation

• Cumulonimbus clouds are tall, dense clouds associated with thunderstorms.
• They can produce hail, heavy rain, lightning, and strong winds.
• Hail forms when strong updrafts inside these storm clouds carry water droplets upward, where they freeze.

Last verified on 09-09-2026

Explanation

• Phosphorus is not among the top 10 most abundant elements in the Earth's crust.
• Most abundant element in Earth crust is Oxygen.
• Oxygen in the crust is (46. 1%).
• The chemical formula of oxygen (dioxygen) is O2.

List of 10 Most Abundant Elements in the Earth's Crust:

Last verified on 01-09-2026