All the organisms that are given here belong to more than one food chain.
The plants are considered as the autotrophs that is the basic level of every food chain. It is consumed by the primary consumers.
Snake is considered as the secondary consumers as it can eat frog, insects, rat et cetera.
Birds can also feed on plants and small insects.
Frog can feed on the butterfly, dragon fly, et cetera.
Insects can eat plants, fruits et cetera.