Explanation:

Statement (a) and (b) are correct: Biomass refers to the quantity or weight of living matter per unit area per unit time. It is represented in terms of dry weight. Biomass is comprised of plants and animals and therefore it is referred to as plant biomass or animal iomass. Total plant biomass including above ground and subsurface plants is called standing crop.

Statement (c) is incorrect: On their basis, the productivity of ecosystem refers to the rate of increases of biomass whereas production is the amount of biomass of a given unit area at a given time. The productivity of continental ecosystems is higher (not lower) than that of marine ecosystems.