How do you create references for journal articles in APA format? If you need to write a psychology paper, then you are going to probably need to reference a number of different journal articles. Such articles summarize the results of studies and experiments conducted by researchers on an enormous range of topics.
The problem that second generation biofuel processes are addressing is to extract useful feedstocks from this woody or fibrous biomass, where the useful sugars are locked in by lignin, hemicellulose and cellulose. All plants contain lignin, hemicellulose and cellulose.
Biofuel is renewable because the process that generates the fuel is ongoing. Trees can be regrown, sewage can be converted into methane, and oil and alcohol can be generated from various plants. Biofuel takes carbon dioxide from the air as the original vegetation grows, and returns it when burnt, so it has a neutral carbon footprint.