Explanation

• Carbon dioxide (CO₂) and oxygen (O₂) move in plants through stomata.
• Stomata are tiny pores present on leaves.
• These gases move by diffusion, not active transport.
• They are essential for photosynthesis and respiration.

Last verified on 25-06-2026

Explanation

• The Sun is the ultimate and main source of energy on Earth.
• It provides energy through solar radiation (light and heat).
• All forms of energy on Earth directly or indirectly come from the Sun.
• It supports life, climate, and ecosystems on Earth.

This energy is then converted into various forms, such as:

• Thermal energy (heat)
• Kinetic energy (wind, water currents)
• Electrical energy (generated from solar panels)
• Chemical energy (fossil fuels, biomass)
• Biological energy (food chains, ecosystems)

Last verified on 16-06-2026

Explanation

• Electric current is the flow of electric charge.
• In metals, this charge is mainly carried by electrons.
• Current is measured in amperes (A).
• Without charge movement, there is no electric current.

Last verified on 25-06-2026

Explanation

• CFCs, carbon dioxide (CO₂), and methane (CH₄) are all greenhouse gases.
• Carbon dioxide traps heat in the atmosphere and increases temperature.
• Methane is a very strong greenhouse gas with high warming effect.
• CFCs also damage the ozone layer and act as greenhouse gases.

Last verified on 16-06-2026

Explanation

• White clothes are worn in hot climate because they reflect most of the sunlight and absorb very little heat.
• This helps keep the body cool in high temperatures.
• Dark colors like black absorb more heat, making the body warmer.

Last verified on 25-06-2026

Explanation

• During a physical change, the chemical composition of a substance does not change.
• Only the state, shape, or size may change.
• No new substance is formed.
• Examples include melting, freezing, and boiling.

Last verified on 25-06-2026

Explanation

• Ocean water is not drinkable due to a high amount of sodium chloride (common salt).
• This salt makes water too salty for human consumption.
• Seawater also contains small amounts of other dissolved minerals.
• High salt concentration causes dehydration in the human body.

Last verified on 25-06-2026

Explanation

• GMO stands for Genetically Modified Organism.
• It refers to an organism whose genetic material (DNA) has been changed using genetic engineering techniques.
• GMOs are developed to improve traits such as disease resistance, increased production, or better quality.

Last verified on 16-06-2026

Explanation

• A rectifier is an electrical device that converts Alternating Current (AC) into Direct Current (DC).
• It allows current to flow in only one direction.
• It is commonly used in power supplies and chargers.
• Rectifiers use components like diodes for conversion.

Last verified on 25-06-2026

Explanation

• The retina is composed of light-sensitive neurons (photoreceptors).
• It detects light and converts it into nerve signals sent to the brain.
• It contains two main cells: rods and cones.
• These cells help in vision, color detection, and low-light vision.

Last verified on 25-06-2026