A carb is a mixture of carbon, oxygen, and hydrogen atoms, and it looks like lots of dots combine and are tightly packed when you are looking at the structure of the atoms and elements.
Definition of a carb: Any of a large group of organic compounds occurring in foods and living tissues. Some of these tissues and foods include sugars, starch, and cellulose. Carbs are broken down in an animal body to provide energy for the organism.
One function of carbohydrates is to provide fuel for the central nervous systeym and energy for muscles. Carbs sometimes prevents protein from being the main source of energy in the body. Carbohydrates also enable fat metabolism. Generally speaking, simple carbs are easily digested and absorbed quicker than other more complex carbohydrates.
.
Citations: science.jrank.com, livescience.com, google.com