What is the major component missing from this food chain in order to see the flow of energy? a) there are no producers b) there should be a higher level consumer c) these fish do not actually live in the same aquatic habitat d) the bird should not be there as it is the only terrestrial organism

The Green plants are missing in the food chain

Explanation:

Producers: The green plants since they produce their own food are also termed as autotrophs. They absorb energy from the sun to make their food. In ocean the phytoplanktons are the producers. In oceans the zooplanktons eat the phytoplanktons. Again the smaller zooplanktons eaten by larger zooplanktons and this eaten by fish. The fish is eaten by a bird. The tertiary consumer.

Consumers: It includes all organism eat something to survive. They might be herbivores and carnivores

Decomposer: The microbes bacteria and fungi converts dead matter into carbon and nitrogen which backs into the atmosphere.

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sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.