The diagram shows an iris and a pupil in different light conditions.
Which characteristic of living organisms is this an example of?
A) growth
B) movement
C) excretion
D) sensitivity
▶️ Answer/Explanation
Ans: D
The diagram demonstrates how the pupil constricts in bright light and dilates in dim light, which is a response to environmental stimuli. This is an example of sensitivity (D), a key characteristic of living organisms.
Growth (A) refers to increase in size, movement (B) involves change in position, and excretion (C) is waste removal. Since the pupil’s response shows reaction to light changes, the correct answer is D (Sensitivity).
A student exposed a fly larva to light and temperature gradients.
They lit the area from one side and made one side of the area warmer than the other.
They traced the path of the fly larva’s movement.
Which statement describes the response of the fly larva?
A) The fly larva does not respond to temperature or light intensity.
B) The fly larva moves away from a higher temperature and a higher light intensity.
C) The fly larva moves away from a higher temperature and a higher light intensity.
D) The fly larva moves towards a higher temperature and away from a higher light intensity.
▶️ Answer/Explanation
Ans: D
The fly larva exhibits thermotaxis (movement towards warmth) and negative phototaxis (movement away from light). The diagram shows it moving towards the warmer side while avoiding brighter regions.
Option A is incorrect as the larva responds to both stimuli. Options B and C are identical and incorrect since the larva moves towards heat. Thus, D is correct, matching the observed behavior.