Scattered through the seas of the world are billions of tons of small plants and animals called plankton. Plankton has been described as the equivalent of the grasses that grow on the dry land continents, and the comparison is an appropriate one. In potential food value, however, plankton far outweighs that of the land grasses. One scientist has estimated that white grasses of the world produce about 49 billion tons of valuable carbohydrates each year, the sea's plankton generates more than twice as much.
According to the passage, why is plankton considered to be more valuable than land grasses?
Select one:
a. It does not require soil.
b. It is more palatable.
c. It is easier to cultivate.
d. It produces more carbohydrates.