Read the following passage and answer the next five questions:
Species interaction and productivity are two important components of any given ecosystem. In an ecosystem, interspecific interactions arise from the interaction of populations of two different species. Such interactions could be beneficial to both species, harmfulto both species, beneficial to one and harmful to the other, or vice-versa. There are also cases where only one species is harmed or benefitted, while the other remains unaffected. On the other hand, the productivity of an ecosystem starts with photosynthesis by green plants and is measured as the amount of biomass produced over a period of time. Such biomass becomes available for consumption to heterotrophs.