Explanation

• Gear is a wheel with teeth along its edge that interlock with another gear to transmit motion and force.
• Gears are used to increase or decrease speed, change direction, or increase torque in machines.
• Common in clocks, bicycles, vehicles, and industrial machines.

Last verified on 16-03-2026

Explanation

• Copper is a chemical element with the symbol Cu and atomic number 29. 
• It is a soft, malleable, and ductile metal with a reddish-orange color.

The some major elements with their symbols:

• Hydrogen - H
• Sodium - Na
• Carbon - C
• Nitrogen - N
• Oxygen - O
• Fluorine - F
• Chlorine - Cl
• Potassium - K
• Helium - He
• Neon - Ne
• Calcium - Ca
• Sulphur - S
• Phosphorus - P
• Aluminium - Al
• Magnesium - Mg
• Iron - Fe

Last verified on 16-03-2026

Explanation

• Sound waves first enter the ear through the Ear Canal.
• It is also known as the external auditory meatus.
• From there, they travel to the eardrum, then to the cochlea, and finally to the auditory nerve.

Last verified on 15-03-2026

Explanation

• Transmission is the process where light passes through a material without being absorbed or reflected.
• The light may pass completely unchanged if the material is transparent.

Additional information:

• Reflection – Light bounces back from a surface
• Absorption – Light is taken in by a material and converted to heat
• Refraction – Light bends while passing from one medium to another (like air to water)

Last verified on 15-03-2026

Explanation

Gears can:

• Change speed: Gears can increase or decrease
• Change direction: Gears can change the direction of rotation
• Change force: Gears can increase or decrease the force

However, gears cannot change the fulcrum, which is the pivot point or axis of rotation.

Last verified on 15-03-2026

Explanation

• Fuel stores energy in the form of chemical bonds.
• When fuel burns in the engine, this chemical energy is converted into mechanical energy to move the car.
• Gasoline, diesel, and natural gas are common fuels storing chemical energy.
• The process of burning fuel to release energy is called combustion.

Last verified on 15-03-2026

Explanation

• Limiting factors are environmental conditions that restrict the growth, abundance, or distribution of organisms.
• They determine which species can survive and how many individuals of each species can exist in an ecosystem.
• Limiting factors can be abiotic (non-living) like sunlight, water, or temperature.
• They can also be biotic (living) like competition, predation, or disease.

Last verified on 15-03-2026

Explanation

• Stomata are tiny pores present mainly on the surface of leaves.
• They allow carbon dioxide (CO₂) to enter the plant for photosynthesis and release oxygen.
• Stomata are controlled by guard cells, which open and close the pores.

Last verified on 15-03-2026

Explanation

• The outer ear (pinna and ear canal) collects sound vibrations from the environment.
• These vibrations travel through the auditory canal to the eardrum (tympanic membrane).

Additional information:

Main Parts of the Ear

• Outer Ear – Pinna and auditory canal
• Middle Ear – Eardrum and three ossicles (malleus, incus, stapes)
• Inner Ear – Cochlea and semicircular canals (hearing and balance)

Last verified on 15-03-2026

Explanation

• Nitrogen (N2) makes up about 78% of the Earth's atmosphere.
• Making it the most abundant gas in the atmosphere.
• It is followed by oxygen (~21%), with other gases in much smaller amounts.

Last verified on 15-03-2026