The correct Answer is Only three
Explanation
An ecosystem comprises all the living organisms in an area interacting with each other and with their non-living environment. Ecosystems can be broadly classified based on their natural occurrence (terrestrial, aquatic) or origin (natural, man-made).
Statement-wise Analysis
- A. Forest - Terrestrial ecosystem
- Correct. Forests are characterized by a dominance of trees and are found on land, making them a prime example of a terrestrial ecosystem.
- B. Estuary - Aquatic ecosystem
- Correct. An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. These are aquatic environments.
- C. Aquarium - Man-made ecosystem
- Correct. An aquarium is an artificial enclosure, typically a tank or container, in which aquatic animals and plants are kept. It is designed and maintained by humans, thus qualifying as a man-made ecosystem.
- D. Biosphere - Local ecosystem
- Incorrect. The biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, geosphere, hydrosphere, and atmosphere. It represents the sum of all ecosystems on Earth and is therefore a global, not a local, ecosystem. Local ecosystems are smaller, distinct units within the biosphere.
Key Takeaway
Ecosystems are classified based on their environment (terrestrial, aquatic) and origin (natural, man-made), with the biosphere representing the largest, global-scale ecosystem.