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

An ecosystem is made up of all the living and non-living organisms in a certain natural environment. The major components of many ecosystems include plants, animals, microorganisms, rocks, water, and insects. The two main categories of ecosystems are; terrestrial and aquatic. The aquatic ecosystem are water-based such as marine, and freshwater, while the terrestrial ecosystems are land-based such as forests, and grasslands.  

true, i don't really know what you're asking but from the info you provided im guessing the answer is true.