Answer:
In grassland ecosystem, first trophic level is the producer. Producers are the organisms which makes their own food, here the producer are grasses. The second trohic level contain herbivores which feed on these grasses. These herbivores are eaten by secondary consumers which belongs to third trophic level and secondary consumers are then eaten by tertiary consumer.
The population of producers are very high so it is placed at the base while tertiary consumer are placed on the top due to low population.
Oxygen and Hydrogen Atoms!
