Pakistan MCQs

Iron is part of the hemoglobin molecule.
Deficiency can reduce oxygen-carrying capacity.

Greenhouse gases slow the escape of heat to space.
The natural effect keeps Earth habitable, but added gases increase warming.

The thyroid incorporates iodine into its hormones.
Deficiency may cause goiter and impaired development.

Coal, oil, and gas release stored carbon when burned.
The resulting carbon dioxide contributes to climate change.

Immunity uses physical barriers, cells, and molecules to defend the body.
It includes innate and adaptive responses.

Methane absorbs infrared radiation efficiently.
It is produced by anaerobic decomposition and livestock digestion.

Vaccines expose the immune system to safe antigenic material.
This creates memory for faster future protection.

These pollutants form sulfuric and nitric acids in air.
Acid deposition can harm lakes, soils, buildings, and forests.

Antibiotics act on features such as bacterial walls or ribosomes.
Viruses use host-cell machinery and lack those targets.

Smog reduces visibility and can irritate the respiratory system.
Some smog forms through sunlight-driven chemical reactions.

Resistance evolves through mutations and selection.
Misuse and overuse of antibiotics accelerate its spread.

Incomplete combustion produces carbon monoxide.
The colorless gas can accumulate dangerously in enclosed spaces.