Explanation

• The sky appears blue due to Rayleigh scattering of sunlight by the atmosphere.
• Shorter wavelengths like blue light scatter more than longer wavelengths (red, yellow).
• The scattered blue light reaches our eyes, making the sky appear blue.
• Red light is less scattered and passes through the atmosphere.

Last verified on 17-03-2026

Explanation

• Ions are charged particles formed when an atom gains or loses electrons.
• Loss of electrons creates a positively charged ion (cation).
• Gain of electrons creates a negatively charged ion (anion).

Last verified on 17-03-2026

Explanation

• Polyvinyl chloride (PVC) is a widely used synthetic polymer.
• It is a solid plastic material at room temperature.
• PVC is used in pipes, bottles, cables, and packaging.
• It is durable, lightweight, and resistant to corrosion.

Last verified on 17-03-2026

Explanation

• A change in physical appearance or state of a substance, such as a change in shape, size, color, or phase (solid, liquid, gas), is called a Physical Change.
  

The are examples of Physical Changes:

• Melting (ice cream, wax, chocolate, ice and change from solid to liquid)
• Phase changes (boiling, freezing, condensation)
• Crushing (chalk)
• Tearing (paper)
• Crumpling (aluminium foil)
• Stretching (rubber band)
• Mixing (sugar in water)
• Dissolving (sugar, salt in water)
• Moulding (clay, metals)
• Slicing (fruit)
• Forming of frost (from water vapors)
• Transition to a gas (change from liquid to gas)
• Change of durability (change in texture or strength)
• Changes to crystal form (change in crystal structure)

Last verified on 17-03-2026

Explanation

• A mature, large ovary and seed are characteristics of a fruit.
• A fruit is the mature ovary of a plant, which contains seeds.
• It typically surrounded by a fleshy, edible pulp.

Last verified on 17-03-2026

Explanation

• Root hairs are tiny tubular outgrowths of roots in plants.
• They increase the surface area of roots for efficient absorption.
• Their main function is to absorb water, mineral salts, and gases from the soil.
• They do not perform photosynthesis or reproduction.

Last verified on 17-03-2026

Explanation

• A sphygmomanometer is a medical device used to measure blood pressure.
• It consists of an inflatable cuff and a pressure gauge.

Last verified on 17-03-2026

Explanation

• Blood vessels and capillaries are part of the circulatory system.
• They transport blood throughout the body, ensuring oxygen and nutrients reach tissues.
• Veins specifically carry blood towards the heart, while arteries carry blood away from the heart.
• Capillaries connect arteries and veins and allow exchange of oxygen, nutrients, and waste.

Last verified on 17-03-2026

Explanation

• Bile, produced by the liver and stored in the gallbladder.
• It breaks down fats into smaller particles, making it easier for enzymes to digest them.
• This process is called emulsification.

Last verified on 17-03-2026

Explanation

• Lung cancer is a disorder of the respiratory tract caused by uncontrolled cell division.
• It leads to the formation of abnormal masses or tumors in the lungs.
• Major types include Small Cell Lung Cancer (SCLC) and Non-Small Cell Lung Cancer (NSCLC).
• Risk factors: Smoking, air pollution, genetic predisposition.
• Symptoms may include cough, chest pain, shortness of breath, and coughing blood.

Last verified on 17-03-2026