Explanation

When a grain of sand enters an oyster's body, the oyster secretes layers of nacre (mother of pearl) around the irritant.

Over time, these layers build up and form a pearl.

Explanation

Smoke is an example of a solid dispersed in a gas, where tiny solid particles are suspended in air.

This type of mixture is a colloidal solution known as an aerosol.

Explanation

Plasma proteins (like albumin, globulin, and fibrinogen) make up 7–8% of plasma by weight.

These proteins help in maintaining osmotic pressure, immunity, and blood clotting.

Explanation

Natural rubber is made primarily of cis-1,4-polyisoprene, a polymer of the isoprene monomer.

It is harvested from the latex of rubber trees and processed into polyisoprene, which gives rubber its elasticity.

Explanation

One day on Venus (one full rotation) takes about 243 Earth days.

Venus takes about 225 Earth days to orbit the Sun, making a day on Venus longer than its year.

So, 1 day on Venus ≈ 1 year on Earth (approximately).

Explanation

Given log₁₂(12³) = x:

Using logarithm properties, logₐ(aⁿ) = n:

x = 3

Explanation

A single chlorine atom from CFCs can destroy up to 100,000 ozone molecules before being deactivated.

This chain reaction is what makes chlorine so dangerous for the ozone layer.

Explanation

Oil and petrol form a thin layer on the water surface, blocking sunlight from reaching underwater plants.

This layer also restricts the mixing of oxygen from the air into the water, harming aquatic life.

Explanation

The term complementarity refers to the specific pairing of nitrogenous bases in DNA: Adenine pairs with Thymine, and Cytosine pairs with Guanine.

This rule ensures accurate DNA replication and structure.

Explanation

Transverse waves in earthquakes are called S-waves (Secondary waves) because they move the ground perpendicular to the wave direction.

P-waves are longitudinal waves, while S-waves are slower and arrive after them.