Living things respond to their environment by adapting to it. Organisms react to different things in their environment, such as light.
Other environmental factors include basic things such as heat, food, odors and sound. When these environmental factors affect or change an organism, they are called stimuli. As the organisms learn to adapt to the stimuli around them, they become better suited for living in the specific environment. For example, camels have long, thick eyelashes. The eyelashes work to protect their eyes from sand since they live in sandy environmental conditions.
Living things also learn how to obtain energy from the environment, and this energy helps them to reproduce. The ability to reproduce is a characteristic of all living things in the world.