Astronauts use $.....$ as a food supplement.

What is $Spirulina$?

How much protein does a $250 \ kg$ cow produce in a day (in $g$)?

The alga rich in protein is

Given below are two statements with respect to single cell protein.
Statement $I$: Single cell protein refers to the crude,or refined edible protein,extracted from pure microbial cultures or from dead or dried cell biomass.
Statement $II$: $SCP$ can be readily used as fodder for achieving fattening of calves,pigs,in breeding fish and in poultry.
In the light of the above statements,choose the correct answer from the options given below.

One of the alternative sources of protein for human and animal nutrition is ........ .