Explanation

• The stomach is an organ involved in digestion, not waste elimination.

1. Lungs: remove carbon dioxide through exhalation
2. Kidneys: filter waste and excess substances from the blood, producing urine
3. Skin: removes waste through sweating
4. Liver: detoxifies harmful substances and aids in their removal

Last verified on 10-03-2026

Explanation

• Reflex actions are rapid, automatic responses to stimuli that occur without the involvement of the brain.
• Instead, they are mediated by the spinal cord or peripheral nerves.

Last verified on 09-03-2026

Explanation

The structure of the brain is similar to the structure of a Walnut, with both having:

• A hard outer layer (cranium vs. shell)
• A wrinkled surface (brain's cerebral cortex vs. walnut's surface)
• A distinct left and right half (brain's hemispheres vs. walnut's halves)

Last verified on 09-03-2026

Explanation

• The nervous system is the body system that controls and coordinates the functions of all other organ systems.
• It allowing for integration and regulation of various bodily functions.
• It consists of the brain, spinal cord, nerves, and sensory organs.

Last verified on 09-03-2026

Explanation

Explanation

Explanation

Explanation

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