An aquarium and Lake Erie can be their own ecosystem
.
Option a and c
Explanation:
An ecosystem is a "community of living organisms" where there is an interaction between the non-living components of the environment and the living components i.e. living organisms, plants, animals, etc. acting as a system.
In the question above, An Aquarium will have its own ecosystem since it is an artificial ecosystem and the organisms present in it are selective and maintained in a restricted environment. While Lake Erie has its own natural ecosystem where all the Aquatic components are in conjunction with each other.
