No, that's not necessarily true. While many plants are green, there are also green animals and even some green fungi.

Here are some examples:

* Animals: Green frogs, green snakes, green caterpillars, green parrots

* Fungi: Some types of mold and lichen can appear green.

The green color in plants comes from chlorophyll, which is essential for photosynthesis. However, other living things can be green for different reasons:

* Camouflage: Green coloration can help animals blend in with their surroundings.

* Pigments: Some animals have pigments in their skin or scales that make them appear green.

* Diet: Some animals can appear green due to the foods they eat, like grasshoppers.

So, while green is a common color for plants, it's not a definitive characteristic that means something is a plant.