Single Cell Protein $(SCP)$ as a food source provides which of the following nutrients?

Spirulina can be grown easily on....

Which branch is useful for cultivating a large number of microorganisms for the production of Single Cell Protein $(SCP)$?

Cyanobacteria of great nutritive value is

Consider the following four statements $(1-4)$ and select the option that includes all the correct statements:
$(1)$ The unicellular $Spirulina$ can produce large quantities of food rich in protein,minerals,vitamins,etc.
$(2)$ $Methylophilus$ $methylotrophus$,because of its high rate of biomass production and growth,can produce $25$ tonnes of protein per day.
$(3)$ Common button mushrooms are rich in Vitamin $C$.
$(4)$ Rice varieties have been developed which are rich in calcium.

In biotechnological studies,the alga that is exploited as a rich source of protein is