An aquarium and Lake Erie can be their own ecosystem
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Option a and c
<u>Explanation:</u>
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.
Since moles are just "some number of particles", and since one O2 molecule contains enough oxygen for two H2O molecules, you need 2.5 moles of O2 for 5 moles of H2O.
