How does broccoli gets its energy?

Plants trap energy from the Sun. Things that eat plants get access to this energy. Raw vegetables have higher minerals and other nutrients. If humans boil, steam, or cook vegetables, much of the nutrients leech into the water used to cook them. So except in soups (which will hold those nutrients), it's important to use some of the boiled liquid either with the serving, or as a basis to make sauces or soups. If you just throw out the water you boiled them in, you'll throw out most of the nutrients. In the body, mastication (chewing) and digestion breaks down the nutrients to give use vitamins, minerals, and energy.