Option no. 2 a decrease in the release of oxygen gas
It is not simple because the process of growing crops, it needs more fertilizers, and processing the plants converting it to fuels needs a lot of energy. As much energy is used during the production from natural gas. The way of making biofuels it contains cellulose. Cellulose
I would say 4. To create a hypothesis, you would need some knowledge about what you're studying. This is where prior knowledge could come in handy.
Sink to the bottom because it is more dense than the water.
