Here's why:
* Simple sugars (monosaccharides) like glucose are the primary fuel for cellular respiration, the process that breaks down food molecules to release energy.
* Complex carbohydrates (polysaccharides) like starch and glycogen are storage forms of energy that can be broken down into simpler sugars when needed.
While other molecules like fats and proteins can also provide energy, carbohydrates are the most readily available and efficient source of immediate energy for most living things.
