Final answer:
Lizards can change color based on their diet, in response to temperature, to attract mates, and as a defense mechanism.
Step-by-step explanation:
The reason why a lizard changes color depends on several factors. In some cases, lizards change color based on their diet (hypothesis A). For example, the diet of some lizards includes plants with pigments that can alter their color. Additionally, lizards can change color in response to temperature (hypothesis B). When a lizard is too hot, it may become lighter in color to reflect sunlight and stay cool.
On the other hand, when a lizard is cold, it may become darker to absorb more heat. Another reason why a lizard changes color is to attract mates (hypothesis C). Bright, vibrant colors can attract potential mates during the breeding season. Finally, lizards can also change color as a defense mechanism (hypothesis D). Some lizards have the ability to blend in with their surroundings, making it difficult for predators to spot them.