In most animals, the gut or digestive tract can be thought of as:

The gut or the digestive tract in most animals can be thought of as the tube that runs from the animal’s mouth to its anus. Hence, this tube transfers food to the organs of digestion. Moreover, this organ system takes in food, digests it to extract and absorb energy and nutrients and expels the remiaining waster as solid waste that is release from the body. 

your body is trying to warm itself up. or more precisely, sensors in your skin send messages to your brain to generate heat to your body.

the sun's light combined with the visible wavelenghts form what is called ultraviolet radiation, which are the long waves at the end of a visible light sprectrum.

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