Pakistan MCQs

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

Catalytic converters promote reactions that reduce carbon monoxide, hydrocarbons, and nitrogen oxides.
They require suitable operating temperature.

Biodegradable materials can be decomposed by bacteria and fungi.
Food scraps and paper are common examples.

Composting uses microorganisms to break down organic matter.
The product can improve soil structure and fertility.

Leaks waste substantial water over time.
Repairing them is a simple and effective conservation measure.

Calcium combines with phosphate in mineralized tissues.
It also supports muscle and nerve function.

Stratospheric ozone absorbs much ultraviolet radiation.
This helps protect living organisms from DNA damage.

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

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

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

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

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