Concept:Ecosystems are divided into natural (occurring without human intervention) and artificial (created or modified by humans).
Explanation:Natural ecosystems include deserts, forests, rivers, and estuaries. They exist freely in nature.
Artificial (man-made) ecosystems are built by humans for various purposes. Examples are aquariums, zoos, farms, crop fields, dams, and gardens.
From the given options, only option B (Aquarium, Zoo and Farming) lists only man-made ecosystems. The other options contain one or more natural ecosystems.
Answer:B. Aquarium, Zoo and Farming