What are the two main categories of ecosystems? a. effective and ineffective b. marine and freshwater c. biotic and abiotic d. aquatic and terrestrial

The right option is; d. aquatic and terrestrial  

The two main categories of ecosystems are aquatic and terrestrial .

An ecosystem is a system that is composed of all the living and non-living organisms in a particular natural environment. The two main categories of ecosystems are aquatic and terrestrial ecosystems. The aquatic ecosystems are water-based (such as marine, freshwater), while the terrestrial ecosystems are land-based (such as forests, deserts). The important components of many ecosystems include animals, plants, microorganisms, water, soil and sunlight.