Explanation

• The cell wall of fungi is primarily made of chitin.
• It is a strong structural polysaccharide that provides support, strength, and protection.

Additional information:

• Cell membrane: Located inside the cell wall and controls the movement of substances into and out of the cell.
• Plants: Their cell walls are mainly made of cellulose.
• Bacteria: Their cell walls typically contain peptidoglycan.

Last verified on 15-10-2026

Explanation

• Respiration is the chemical process in which energy is released from food.
• Cells break down glucose to release energy for various life activities.
• Aerobic respiration uses oxygen, while anaerobic respiration occurs without oxygen.
• The released energy is stored mainly in the form of ATP (adenosine triphosphate).

Additional information:

• Nutrition: Taking in and using food.
• Digestion: Breaking down food into simpler substances.

Last verified on 10-10-2026

Explanation

• The Earth's outermost layer is called the Crust.
• The crust is the thin, solid outer layer where humans, animals, and plants live.
• It is located above the mantle, outer core, and inner core.
• It is made mainly of rocks and minerals.

Additional information:

• Earth's Layers (Outer to Inner): Crust → Mantle → Outer Core → Inner Core
• Crust Thickness: About 5–70 km
• Mantle Thickness: About 2,900 km
• Outer Core Thickness: About 2,260 km
• Inner Core Radius: About 1,220 km

Last verified on 04-08-2026

Explanation

• The lungs exchange gases — they absorb oxygen (O₂) and release carbon dioxide (CO₂).
• This process is essential for respiration and energy production in the body.

Last verified on 05-09-2026

Explanation

• Paleolithic = Old Stone Age; people hunted animals and gathered wild plants.
• "Old Stone Age," the earliest and longest human era (roughly 2.6 million years ago to about 10,000 BCE).

Explanation

Sandra Harding

• Developed feminist epistemology; identified three approaches:
• Feminist empiricism (1986, The Science Question in Feminism)
• Standpoint theory (1991, Whose Science? Whose Knowledge?)
• Postmodern feminism (1986, later works)

Additional information

• Simone de Beauvoir — The Second Sex (1949)
• Judith Butler — Gender Trouble (1990)
• Betty Friedan — The Feminine Mystique (1963)

Explanation

• The Chalcolithic Period (also called the Copper Age):
• Marks the transition between the Stone Age and the Bronze Age
• Defined by the simultaneous use of stone and copper tools
• Name comes from the Greek chalcos (copper) and lithos (stone)
• It's the period when humans first began working with metal

Explanation

• Mangrove forests are found in the Indus Delta region of Sindh.
• The Indus Delta is located where the Indus River meets the Arabian Sea.
• It consists of a network of creeks, estuaries, and distributaries.

Additional information:

• Coniferous Forests → Khyber Pakhtunkhwa, Gilgit-Baltistan, AJK
• Juniper Forests → Ziarat, Balochistan
• Riverine Forests → Along the Indus River in Sindh and Punjab
• Subtropical Pine Forests → Murree, Abbottabad, Hazara region

Verified & Updated

Explanation

• Fish survival decreases due to the decomposition of organic matter.
• When organic matter increases, bacteria decompose it and consume dissolved oxygen.
• Low oxygen levels make it difficult for fish to breathe.
• This can lead to fish stress or even fish kills.
• Excess organic matter also reduces overall water quality.

Last verified on 11-07-2026

Explanation