Biomass comes from plants and animal waste. Like solar and wind energy, biomass is also a renewable resource. But unlike solar energy, you can find biomass anywhere, as long as there are plants or animals. With solar energy you need sun. And with wind energy, you need wind. So in my opinion, biomass is easier to find. But why is biomass a renewable resource? It's simple, since biomass is mostly from plants, you get photosynthesis, which comes from the sun. And chlorophyll, which also occurs in plants, converts carbon dioxide from the air, and water from the ground, to carbon, oxygen, and hydrogen compounds. When this stuff is burned it turns back into carbon dioxide, but it also releases the solar from the sun. So in a way, biomass can also be bad by causing some pollution, but for most part, it is good.
Biomass can be found in anything from grass to trees to urban waste. According to "Clean Energy: How Biomass Energy Works," biomass is one of the first renewable resource known to humans.
We have been using biomass for thousands of years, although lots of people don't know it. A long time ago, people use to burn it for heat. We still use biomass in the same way, but now we use it for cooking and even for producing electricity. Maybe in the future, we can use biomass to power our houses or even our cars!