By 2020 A.D.,Human beings will be compelled to look for other sources for their food.Mushroom may be grown artificially , because they reproduce principally by spores, sometimes producing these at the rate of 40,000,000. an hour.
Algae could be cultivated about thirty meters below the surface of the sea by establishing special "farms". These algae could help reap a rich "harvest" of fish for man.
Source:Tinkle