Explanation

• Markhor is the national animal of Pakistan.
• “Markhor” means “snake eater.”
• It is known as a symbol of bravery and sharp intelligence.
• It is large wild goat (Capra species).
• It is found in Central Asia, the Karakoram, and the Himalayan regions.

Explanation

Humans have 22 pairs of autosomes and 1 pair of sex chromosomes.

Chromosome 21 is the smallest autosome in terms of base pairs.

Chromosome 1 is the largest autosome.

Chromosome 23 refers to sex chromosomes (X or Y), not autosomes.

Chromosome 21 is associated with Down syndrome when trisomic.

Last updated question 17-02-2026

Explanation

• Oxidation state indicates the number of electrons an atom has gained or lost.
• Moving from –3 → 0 means the element loses 3 electrons.
• Loss of electrons is called oxidation.
• This process increases the element’s oxidation number.
• Example: Nitrogen in NH₃ (–3) → N₂ (0) during oxidation.

Last updated question 17-02-2026

Explanation

• Cell membrane contains phospholipids, proteins, and glycoproteins.
• Glycoproteins form a sticky outer layer (glycocalyx).
• This layer slows the movement of molecules across the membrane.
• Glycolipids also reduce diffusion slightly, but less than glycoproteins.
• Glycerol does not affect cell diffusibility significantly.

Last updated question 17-02-2026

Explanation

Explanation

Explanation

• Copper has two common oxidation states: +1 (cuprous) and +2 (cupric).
• In CuO, copper is +2 (Cu²⁺) → cupric oxide.
• In CuBr, copper is +1 (Cu⁺) → cuprous bromide.
• CuCl₂ and CuSO₄ also have copper in +2 state.
• The +1 state is more stable with less electronegative elements like bromine.

Explanation

Amaranthaceae is a family of flowering plants (e.g., Amaranthus).

Flowers are usually small and inconspicuous.

Petals are absent in most species; flowers are apetalous.

Sepals are present and protect the flower.

Leaves and stems are present as normal vegetative structures.

Last updated question 17-02-2026

Explanation

• The nephron is the functional unit of the kidney.
• Sodium reabsorption occurs at different parts of the nephron.
• Thick loop of Henle actively pumps out Na⁺ using ATP (active transport).
• Thin loop of Henle mainly allows passive movement of water and ions.
• Proximal tubule reabsorbs Na⁺ mainly by secondary active transport; collecting duct fine-tunes Na⁺ under hormonal control (aldosterone).

Last updated question 17-02-2026

Explanation