Plant (producer) → Insect (herbivore) → [M] (primary carnivore) → Snake (secondary carnivore) → Eagle (top carnivore)
The missing link M must be:
(A) Rabbit - incorrect (herbivore, doesn't eat insects)
(B) Wolf - incorrect (higher carnivore, wouldn't be eaten by snakes)
(C) Frog - correct (insectivorous and preyed upon by snakes)
(D) Ichthyophis - incorrect (a legless amphibian that snakes wouldn't typically eat)
Thus, the complete chain is:
Plant → Insect → Frog → Snake → Eagle
Plant → Insect → M → Snake → Eagle
Answer: (C) Frog
In this food chain, we are looking for an organism that:
The other options, such as Rabbit (which typically feeds on plants and is not usually preyed upon by snakes as often as frogs), Wolf (which is a carnivore and not part of this food chain), and Ichthyophis (a type of amphibian not as common in this context) are not suitable.
In the given graph, \( E_a \) for the reverse reaction will be