Pros- We wouldn't need to use fossil fuels as much (which we have a limited supply of) and we have an unlimited supply when using Biomass as enegy.
It actually produces more oxygen when growing biomass crops and uses up carbon dioxide.
While for cons...
There's more work when it comes to growing and handling these crops, and this lifestyle in general.
more money and resources that we do not always have.
We don't always have a certain animal waste - which can slow down the process a little more if there's not enough of a certain thing. But of course referencing the pro side of things - we will always be able to produce biomass energy through things such as dead plants, etc.
I hope this helps, and you pass! Good luck, rockstar! (: