▶️ Answer/Explanation
The correct answer is B.
At position M (roots), the plant grows towards gravity ($+$ gravitropism) and away from light ($-$ phototropism) to anchor itself and reach water. At position N (shoots), the plant grows against gravity ($-$ gravitropism) and towards light ($+$ phototropism) to maximize photosynthesis.This differential response ensures the plant is correctly oriented for survival. Row B accurately reflects these biological directions, showing positive gravity/negative light responses for roots and the opposite for shoots.
▶️ Answer/Explanation
Limewater, which is a solution of calcium hydroxide $Ca(OH)_2$, is the standard reagent used to detect the presence of carbon dioxide $CO_2$. When $CO_2$ is bubbled through limewater, it reacts to form calcium carbonate $CaCO_3$, an insoluble white precipitate that turns the solution “milky” or cloudy. In contrast, DCPIP is used to test for Vitamin C, ethanol is used in the emulsion test for lipids, and iodine solution is the specific indicator for starch. Therefore, only limewater provides a visible diagnostic result for carbon dioxide gas.
✅ Answer: (D)
Question
Which actions use energy released from respiration?
1 muscle contraction
2 protein synthesis
3 cell division
4 transmitting nerve impulses
(A) 1, 2, 3 and 4
(B) 1, 2 and 4 only
(C) 2 and 3 only
(D) 3 and 4 only
▶️Answer/Explanation
Ans: A