Answer: A
Biomass energy is the energy provided by living plants in nature. These plants use biomass as a means of storing solar energy and are renewable energy sources. It is calculated that the energy stored in biomass is twice the current total energy consumption in the world. The first energy used in human history was biomass energy. Before the second half of the 19th century, the energy used by man was mainly firewood. Currently, the most efficient ways to use biomass energy are: ① Producing biogas. It mainly uses urban and rural organic waste, straw, water and human and animal excreta to produce methane, a flammable gas, through anaerobic digestion for living and production purposes. ②Use biomass to produce alcohol. In the energy structureIn the current world, biomass energy only represents a very small proportion.