What is the source of all energy in the pyramid?

Sunlight is your answer.

The whole pyramid must be sustained by the base. Without the base, the whole pyramid would not exist. The same is for the food pyramid. The producers must be present for consumers to be able to survive. Without it, the whole pyramid would collapse. Without sunlight, the plants would die. Without plants, the herbivores would die. Without herbivores, the carnivores would die, etc. etc.

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carbon

explanation: