Explanation

• In fluvial processes, small and shallow channels are called rills, which grow into gullies,

Additional information

• Valleys: Large, low-lying areas drained by rivers or streams.
• Deltas: Landforms created at the mouth of a river where it meets standing water.
• Levees: Raised ridges of sediment running along the banks of a river channel.

Explanation

• The visible light spectrum for the human eye generally ranges from approximately 380 to 750 nanometers (nm), with standard limits often cited from 400 to 700 nm. 

Wavelength Ranges by Color

1. Violet: 380 nm to 450 nm
2. Blue: 450 nm to 485 nm
3. Green: 485 nm to 500 nm
4. Yellow: 500 nm to 565 nm
5. Orange: 565 nm to 625 nm
6. Red: 625 nm to 750 nm 

Last updated 27-07-2026 by NA

Explanation

• Slate is a metamorphic rock.
• It is mainly formed from shale or mudstone.
• Formation occurs under low-grade heat and pressure.
• Volcanic ash can also contribute to its formation.
• Type: Fine-grained, foliated metamorphic rock.

Last updated 27-07-2026 by NA

Explanation

• SI stands for the International System of Units
• The world's standard modern metric system used for science, commerce, and everyday measurements.

The SI system is built upon seven fundamental base units: 

1. Metre (m) – for length
2. Kilogram (kg) – for mass
3. Second (s) – for time
4. Ampere (A) – for electric current
5. Kelvin (K) – for thermodynamic temperature
6. Mole (mol) – for amount of substance
7. Candela (cd) – for luminous intensity 

Last updated 27-07-2026 by NA

Explanation

• When tectonic plates slide past each other, they form faults or fault lines.
• This type of plate boundary is called a transform boundary.
• Movement along fault lines can cause earthquakes.
• A famous example is the San Andreas Fault in California, USA.

Last verified on 28-97-2026

Explanation

• A horst is an uplifted block of the Earth's crust formed between two parallel normal faults.
• It is created by tectonic forces during crustal extension.
• The adjacent blocks move downward, making the horst appear elevated.

Additional information:

• Graben: Down-faulted block between two normal faults
• Normal fault: Forms due to tensional forces
• Reverse fault: Forms due to compressional forces
• Strike-slip fault: Forms due to horizontal shearing forces

Last verified on 28-07-2026

Explanation

• Einstein's equation E=mc² shows that mass can be converted into energy and vice versa.
• c: Speed of light = 299,792,458 m/s (≈ 3×10⁸ m/s)
• E: Energy
• m: Mass
• It was proposed by Albert Einstein in 1905 as part of the Special Theory of Relativity.

Last verified on 28-07-2026

Explanation

• Cow and Deer are herbivores because they feed on plants.
• Herbivores eat grass, leaves, fruits, and other plant materials.

Additional information:

• Herbivores: Cow, Deer, Goat, Rabbit, Elephant
• Carnivores: Lion, Tiger, Leopard, Wolf, Cheetah
• Omnivores: Human, Bear, Crow, Pig, Hen

Last verified on 27-07-2026

Explanation

• Paramecium contains two nuclei: a macronucleus and a micronucleus.
• The macronucleus controls daily metabolic and cellular activities.
• The micronucleus is responsible for reproduction and genetic exchange.
• Paramecium is a single-celled protozoan found in freshwater.
• It belongs to the phylum Ciliophora.

Last verified on 27-07-2026

Explanation

• Lahore's smog is mainly caused by pollutants from vehicles reacting with sunlight.
• Nitrogen oxides (NOₓ) and volatile organic compounds (VOCs) form ground-level ozone and fine particles.
• Industrial emissions, crop residue burning, and brick kilns also worsen smog.
• Smog is most severe during the winter season (October–January).

Last verified on 27-07-2026