Explanation

A magnetic compass needle aligns itself with the Earth’s magnetic field.

Therefore, it always points in the North-South direction.

Explanation

The solar energy that reaches the Earth annually is far more than the world's total energy consumption, with estimates suggesting it is more than 10,000 times the current global energy needs.

This vast amount of energy highlights the potential of solar power as a renewable energy source.

Explanation

Polymerization is the process where small molecules (monomers) repeatedly bond to form large molecules (polymers).

It's commonly used in making plastics, synthetic fibers, and resins.

Explanation

Aestivation is a state of inactivity or dormancy that animals enter during hot or dry seasons to conserve energy.

Hibernation, in contrast, occurs during winter when animals become inactive to survive cold temperatures.

Explanation

Polythene bags are synthetic plastics that do not decompose naturally, taking hundreds of years to break down.

Unlike organic materials like feathers, paper, and wood, polythene bags contribute to environmental pollution.

Explanation

Aerobic exercise requires oxygen to generate energy, improving cardiovascular endurance.

Examples include running, swimming, and cycling, which help strengthen the heart and lungs.

Explanation

Vitamin K is essential for blood clotting.

Its deficiency can lead to excessive bleeding (haemorrhage).

It helps produce clotting factors in the liver, preventing uncontrolled bleeding.

Explanation

Medicine in a teaspoon is measured in milliliters (mL) as it is a small liquid quantity.

A standard teaspoon holds approximately 5 mL of liquid.

Explanation

Cytosine is found in both DNA and RNA, but uracil is unique to RNA.

In RNA, uracil replaces thymine, pairing with adenine during transcription.

Explanation

100 grams of cooked white rice contains approximately 360 kcal, depending on the variety.

Rice is a major carbohydrate source, providing energy for daily activities.