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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answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.