Answer:
'The rule of 10' is associated with the pyramids of quantifying energy flow.
Only a small amount of energy is transferred from one trophic level to another. Most of the energy is lost in the form of heat. Hence, we quantify that about 10% of energy travels from one trophic level to another.
Let's say the producers have 100% energy. The primary consumers will only receive 10% of this energy. The secondary consumers will receive 1% energy from the primary consumers. The tertiary consumers will receive 0.1% energy. This is known as the rule of 10.