Practise 31 real Federal Board questions on Homeostasis from 2023 to 2026. See the answer and explanation as soon as you answer.
Homeostasis is one of the 15 main chapters in our Federal Board FSC Biology question bank (11th and 12th class), and about 6% of its real questions come from it. Tayyari Karo has 31 real questions on this chapter from 2023 to 2026; 10 are multiple choice and marked instantly, and the rest are short and long questions with a model answer. By difficulty: 26 medium, 3 easy, 2 hard.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
These are real past-paper questions. Think of your answer first, then open the explanation.
Shivering in humans helps to:
Answer: C. Increase heat production
Shivering is rapid, involuntary muscle contraction that generates extra metabolic heat to raise body temperature in cold conditions.
Tubular secretion involves the movement of substances from:
Answer: C. Blood to filtrate
Tubular secretion is the active transport of substances (e.g. H⁺, K⁺, drugs) from the peritubular blood capillaries into the tubular filtrate.
Which response would help compensate for low O₂ levels at high altitudes?
Answer: A. Increased breathing rate
At high altitude, low oxygen availability is compensated by increasing breathing (ventilation) rate to take in more air and increase oxygen uptake.
The nitrogenous waste excreted by sparrow is:
Answer: B. Uric acid
Birds (like sparrows) excrete nitrogenous waste mainly as uric acid, a semi-solid, low-water-loss form of excretion suited to flight and egg-laying.
Which one of the following structures filters blood at high pressure to form glomerular filtrate?
Answer: D. Renal corpuscle
The renal corpuscle (glomerulus + Bowman's capsule) filters blood under high hydrostatic pressure to produce the glomerular filtrate.
After consuming banana, which hormone would be expected to increase in body?
Answer: C. Insulin
Bananas are rich in sugars; the resulting rise in blood glucose stimulates the pancreas to secrete more insulin.
Describe the mechanism involved in opening and closing of stomata by K⁺ ion influx/efflux theory.
The K⁺ ion (potassium) theory explains stomatal movement through changes in guard cell turgor driven by potassium ion transport:
Opening: in light, guard cells actively pump H⁺ ions out (using ATP-driven proton pumps), creating an electrochemical gradient. This drives K⁺ ions to move into the guard cells through specific K⁺ channels. The resulting increase in solute concentration lowers the guard cells' water potential, so water enters by osmosis, increasing turgor pressure; because the guard cell walls are thicker on the inner side, the cells bow outward, opening the stomatal pore. …
The full model answer is in the app.
Explain briefly the mechanism of water and electrolyte balance in the human body.
Water and electrolyte balance is regulated mainly by the kidneys under hormonal control. A rise in blood osmolarity (water loss) is detected by hypothalamic osmoreceptors, triggering ADH release from the posterior pituitary, which increases water reabsorption in the kidney's collecting ducts, concentrating urine and conserving water. Aldosterone, from the adrenal cortex, promotes Na⁺ reabsorption (and K⁺ excretion) in the kidney tubules, and water follows sodium osmotically, helping maintain both electrolyte and fluid balance. Thirst mechanisms also stimulate water intake when osmolarity rises.
| Session | Questions |
|---|---|
| 2026 Annual | 9 |
| 2025 1st Annual | 6 |
| 2025 2nd Annual | 7 |
| 2024 Annual | 5 |
| 2023 Annual | 4 |
31 real Federal Board (FBISE) Biology questions on Homeostasis from 2023 to 2026, for 11th and 12th class. Each one shows the session it came from.
No. We could not find an official FBISE marking scheme for these papers, so the answers and explanations are written by Tayyari Karo for practice. Check anything important with your teacher or textbook.
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