Explanation

• Endosmosis is the movement of water into a cell through a selectively permeable membrane.
• Pure water is hypotonic compared to the cell sap, so water enters the plant cell by osmosis.
• The plant cell becomes turgid (swollen and firm) due to the entry of water.
• The cell wall prevents the plant cell from bursting under normal conditions.

Last verified on 02-11-2026

Explanation

• Motor nerves carry signals from the control centre (brain or spinal cord) to effectors.
• Effectors, such as muscles and glands, produce the required response.
• Sensory nerves carry information from receptors to the control centre.
• The pathway is: Receptor → Sensory nerve → Control centre → Motor nerve → Effector.

Last verified on 02-11-2026

Explanation

• Receptors detect changes (stimuli) in the internal environment of the body.
• They send nerve signals to the control centre, usually the brain or spinal cord.
• Examples include thermoreceptors, chemoreceptors, and pressure receptors.
• Effectors, such as muscles and glands, produce responses to maintain homeostasis.

Last verified on 02-11-2026

Explanation

• The liver is considered the main centre of metabolism because it regulates carbohydrates, proteins, and fats.
• It converts excess glucose into glycogen for storage and helps regulate blood sugar levels.
• The liver also detoxifies harmful substances and produces bile for fat digestion.
• It is the largest internal organ of the human body.

Last verified on 02-11-2026

Explanation

Iron deficiency can lead to Anaemia, a condition characterized by:

• Low red blood cell count
• Pale skin
• Fatigue
• Shortness of breath
• Dizziness

Last verified on 02-11-2026

Explanation

• Decomposers break down dead plants, animals, and organic waste into simpler substances.
• They return essential nutrients to the soil and environment, making them available for reuse by producers.
• Examples include bacteria and fungi.
• Decomposers play an essential role in maintaining nutrient cycles, such as the carbon and nitrogen cycles.

Last verified on 02-11-2026

Explanation

• The biosphere is the highest level of biological organization because it includes all ecosystems on Earth.
• The order of ecological organization is organism → population → community → ecosystem → biosphere.
• The biosphere includes all regions of Earth where life exists, including land, water, and parts of the atmosphere.

Last verified on 02-11-2026

Explanation

• Renewable resources are resources that can be naturally replenished through physical or biological processes.
• Examples include sunlight, wind, water, and forests when managed sustainably.

Additional information:

• Non-renewable resources, such as coal, petroleum, and natural gas, take millions of years to form and cannot be replaced quickly.

Last verified on 02-11-2026

Explanation

• Evolution refers to the gradual development or change of something over time.
• In biology, evolution explains how living organisms change over generations.
• Charles Darwin is widely known for developing the theory of evolution by natural selection.

Last verified on 02-11-2026

Explanation