Answer:
Because primary producers get 100% energy consumption straight from the sun.
Step-by-step explanation:
We use the energy pyramid to help us out:
.01% - A pex Predators
0.1% - Tertiary Consumers
1% - Secondary Consumers
10% - Primary Consumers
100% - Primary Producers
Because Primary Producers get 100% of the energy of the sun, they can support so many primary consumers, who only get 10% of the energy when they consume primary producers.