Answer:
Protists are eukaryotic organisms that cannot be classified as a plant, animal, or fungus. They are mostly unicellular, but some, like algae, are multicellular. ... Protists can be heterotrophic, which means they obtain the energy they need to live by consuming other organisms.
Explanation:
From Google
Biomass is plant or animal material used as fuel to produce electricity or heat. Therefore i think the answer is plants!
Megacity would probably have the biggest affect on the immediate environment and possible the outlands of the megacity as well.
Answer:
absorption of water and minerals in plants
In a way, yes.
experiments need a hypothesis (this would correspond to "what they already believe") which has to be a specific proposal, not a question (e.g. turtles reproduce sexually)
their experiments proove (or, better said: test!) whether "what they already believe" is true.