Plants are important to animals as animals rely on them for food, oxygen and habitat maintenance. Without plants, animals would not be able to meet their basic needs. As much as animals depend on plants, plants depend on animals too.
Animals are unable to produce their own food, and as plants are primary producers they sustain animals in a couple of ways. While herbivores depend on them for sustenance, other animals rely on plants sustaining their prey. In addition, plants produce oxygen via photosynthesis. This involves taking energy from the sun and carbon dioxide from the air to produce glucose and oxygen as by-products. While the plant consumes the glucose to keep itself alive, oxygen releases into the air for animals to breathe.
Many animals depend on plants for their habitats. For example, birds nest in trees. In addition, some animals require a cool and dark environment, which they could not find without plants offering shade. Some also need trees to offer shelter from the rain and the sun, and others need a forest floor to live on, like insects.
In terms of human dependence, plants provide the resources needed to produce clothes and medicines. Some plants rely on animals to remain alive. For example, animals help to spread seeds and bees pollinate flowers, allowing plants to grow. In addition, without animals eating each other, plant-eating animals would eat too many plants. Finally, earthworms play a role in bringing air into soil, which helps plants thrive.