CBSE Class 10 Science 2022 · Paper 31/6/1 · Question 7(a)

(i) Crop fields are considered artificial ecosystems because they are created and maintained by human beings. People decide which crop is grown and control its conditions: they prepare the soil, sow the seeds, irrigate, add manure and fertilisers, remove weeds, control pests and harvest the crop. Without this human care the field would not continue as a crop field, unlike a natural ecosystem such as a forest or a pond, which maintains itself. (ii) Grass $\to$ Grasshopper $\to$ Frog $\to$ Snake (producer, herbivore, carnivore and top carnivore of the chain: four trophic levels).