Explanation

• The thickness of Earth is about 13,700 kilometers (8,500 miles).
• The mantle, which is the biggest part of Earth by volume.
• It is approximately 2,900 kilometers (1,800 miles) thick. 

Last verified on 09-06-2026

Explanation

• Herpetology is the branch of zoology that studies reptiles and amphibians.
• Reptiles include: snakes, lizards, crocodiles, turtles.
• Amphibians include: frogs, toads, salamanders.
• The word comes from Greek “herpeton” meaning creeping animal.

Last verified on 09-06-2026

Explanation

• The splitting of light into its constituent colors is called dispersion.
• White light splits into seven colors (VIBGYOR).
• It occurs when light passes through a prism.
• Different colors bend at different angles.
• This creates a spectrum of colors.

Last verified on 08-06-2026

Explanation

• Liver produces bile, which helps in digestion of fats in the human body.
• Bile is a digestive fluid essential for fat breakdown.
• It is produced continuously by the liver.
• It is stored and concentrated in the gallbladder.
• It is released into the small intestine during digestion.

Last verified on 08-06-2026

Explanation

• The ecosystem is the structural and functional unit of the environment.
• Ecosystem = Biotic + Abiotic components
• Biotic: plants, animals, microorganisms
• Abiotic: water, air, soil, sunlight

Last verified on 08-06-2026

Explanation

When white light passes through a prism, it splits into 7 colors, forming a spectrum known as a rainbow:

1. Red
2. Orange
3. Yellow
4. Green
5. Blue
6. Indigo
7. Violet

The separation of visible light into its different colours is known as dispersion.

Last verified on 08-06-2026

Explanation

• The SI unit of electric current is Ampere (A).
• Electric current measures the flow of electric charge.
• Defined using the elementary charge (e = 1.602176634 × 10⁻¹⁹ C).
• Named after: André-Marie Ampère (scientist).
• 1 Ampere = 1 Coulomb per second (1 A = 1 C/s).

Last verified on 08-06-2026

Explanation

• Sublimation is the direct transition of a solid into a gas without passing through the liquid phase.

Additional information:

Some common sublimating substances:

• Dry ice (CO₂) – solid → gas
• Iodine crystals – solid → violet gas
• Camphor – solid → vapor
• Naphthalene (mothballs) – solid → gas
• Ammonium chloride – solid → gas

Last verified on 13-03-2026

Explanation

• Mitochondria are called the powerhouse of the cell.
• Because they produce Adenosine Triphosphate (ATP).
• ATP is the energy currency of the cell.
• ATP provides energy for different cellular activities such as movement, growth, and transport.
• Energy is produced through aerobic cellular respiration using oxygen and الغذائی molecules.
• They are found in the cytoplasm of most eukaryotic cells.
• Richard Altmann first described mitochondria in 1890.

Main Parts of a Cell:

1. Cell membrane → Outer protective layer
2. Nucleus → Controls cell activities
3. Cytoplasm → Jelly-like material between membrane and nucleus

Last verified on 09-05-2026

Explanation

• Neurons are the basic structural and functional units of the nervous system.
• They are specialized nerve cells.
• They transmit electrical and chemical signals.
• They control communication in the body.
• Brain, spinal cord, and nerves are made up of neurons.

Last verified on 08-06-2026