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

• 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

• Carolus Linnaeus gave the artificial system of classification. 
• He classified plants mainly based on the number and arrangement of stamens.
• known as the "Father of Taxonomy

Last updated question 17-02-2026

Explanation

• Energy transfer in a food chain follows the 10% law.
• Only about 10% of energy passes to the next trophic level.
• About 90% of energy is lost as heat and metabolic activities.
• This loss limits the number of trophic levels in a food web.
• Therefore, energy decreases by approximately 90% at each step.

Last updated question 17-02-2026

Explanation

• DNA sequencing by Sanger method uses ddNTPs.
• ddNTPs lack the 3′-OH group on the sugar.
• Without 3′-OH, no further nucleotide can attach.
• This causes termination of the DNA chain.
• Different labeled ddNTPs help determine the DNA sequence.