Found in both animal sources (meat, fish, eggs, cheese) and vegetables (beans, nuts, some grains), proteins are important for the body's maintenance, growth, and repair.

Radiation occurs when electromagnetic waves transmit heat. An example is the heat from the Sun as it travels to Earth.

Secondary consumers (carnivores) subsist mainly on primary consumers. Omnivores are secondary consumers that also eat producers. Examples are rats, fish, and chickens.

Part of the peripheral nervous system, the somatic nervous system is made up of nerve fibers that send sensory information to the central nervous system and control voluntary actions.

Vitamins are necessary for a wide variety of bodily processes. Some vitamins like Vitamins A and C come from diet but others, like Vitamin D, are generated in response to sunlight.