Which environmental stimulus do a flatworm's eyespots primarily detect?

• A. Temperature
• B. Sound
• C. Light
• D. Chemical signals

Answer: (C)

Verified step by step guidance

1. Understand the function of eyespots in flatworms: Eyespots are simple sensory structures that help flatworms detect environmental stimuli, specifically light intensity and direction.
2. Recognize that flatworms use their eyespots to navigate their environment by moving toward or away from light sources, which aids in survival and finding suitable habitats.
3. Eliminate incorrect options: Temperature, sound, and chemical signals are not primarily detected by eyespots. These stimuli are sensed by other specialized structures or mechanisms in organisms.
4. Focus on the correct option: Light is the primary environmental stimulus detected by flatworm eyespots, as they are photoreceptive organs.
5. Conclude that flatworm eyespots are adapted for detecting light, which is crucial for their behavior and interaction with their surroundings.