Concept:Counter-shading is a camouflage pattern in which the upper part of an animal is darker than the lower part.
This two-tone colouration reduces the animal's contrast against its background.
Explanation:A fish has a dark dorsal (back) surface and a light ventral (belly) surface.
When viewed from above, the dark back blends with the darker water below.
When viewed from below, the light belly blends with the brighter water surface.
This cancels the shadow formed by sunlight, making the fish harder for predators to detect.
A grasshopper mainly matches green or brown vegetation for camouflage, not counter-shading.
A toad uses mottled skin to blend with soil and leaves on the ground.
A chameleon changes its colour actively to match its surroundings, which is different from counter-shading.
Among the given options, fish are the classic example of counter-shading.
Answer:C. fish