Explanation

The state of inactivity in animals during summer or dry season is called aestivation (or estivation).

Purpose: To conserve energy and prevent water loss during arid, high-temperature conditions.

Duration: Lasts for the duration of the hot/dry season, ranging from weeks to months, or even years in some cases.

Explanation

Double fertilization occurs in angiosperms like Brassica

Where one sperm fertilizes the egg, and another fuses with the central cell to form endosperm.

Bryophytes and gymnosperms (e.g., pine).

Last updated 17-02-2026

Explanation

Water is essential for survival as it supports biological functions in humans, animals, and plants.

It is needed for digestion, circulation, photosynthesis, and maintaining life processes.

Explanation

Elephants have 56 chromosomes in total, which means 28 pairs.

These chromosomes carry genetic information essential for their growth, reproduction, and survival.

Explanation

 Closed System:

In a closed system, social status is largely determined at birth and individuals have limited or no ability to move up or down the social hierarchy. 

Examples of Closed Systems:

Traditional caste systems and feudal estate systems are examples of closed systems where social mobility is severely restricted

Explanation

 Anaerobic Organisms: Anaerobic organisms, including certain bacteria, are those that do not require oxygen for growth and survival. 

Oxygen Toxicity: Some anaerobic bacteria are highly sensitive to oxygen and cannot tolerate its presence, while others can tolerate small amounts of oxygen. 

Explanation

Explanation

Animals cannot use atmospheric nitrogen directly; they obtain nitrogen by consuming proteins in food.

These proteins are broken down into amino acids, which are used for growth and repair of body tissues.

Explanation

Cellulose is a structural component of plant cell walls, absent in animal cells.

Animal cells lack a rigid cell wall and instead have a flexible plasma membrane.

Explanation

Pertussis is commonly known as whooping cough.