Explanation

• The primary component of natural gas is methane (CH4).
• Making up 70% to 90% or more of its composition.
• It is a colorless, odorless, and highly flammable hydrocarbon gas.
• Characteristics: It is a fossil fuel, often found in rock formations alongside oil or on its own. 

Last updated question 15 March2026

Explanation

• Carbon dioxide (CO2) is the gas from the atmosphere that plants absorb through their leaves.
• It use as a reactant in photosynthesis, combining it with water and light energy to produce glucose and oxygen.

Explanation

Primary pollutants are emitted directly into the air from sources like vehicles and industries.

Examples include carbon monoxide (CO), sulfur dioxide (SO₂), and nitrogen dioxide (NO₂).

Explanation

Hydrogen is present in the atmosphere in trace amounts, making it the least common among the listed gases.

Nitrogen (~78%), Oxygen (~21%), and Argon (~0.93%) are much more abundant.

Explanation

Radon (Rn) is a radioactive gas formed from the decay of uranium and radium found in rocks and soil.

He (Helium): Helium is present in trace amounts in the atmosphere.

Ne (Neon): Neon is also present in trace amounts in the atmosphere.

Ar (Argon): Argon is the most abundant noble gas in Earth's atmosphere, making up about 0.93% of the air. 

Explanation

A community is formed when populations of different species live and interact in the same area.

It represents the biotic (living) component of an ecosystem.

Explanation

Explanation

A food chain always begins with producers.

It usually green plants or algae, that make their own food through photosynthesis.

Explanation

Explanation

• Ozone gas is a molecule made up of three oxygen atoms, with the chemical formula O3.
• This is different from ordinary oxygen, which has the chemical formula O2.