Power and strength
Katara walked by the edge of the river. She, Aang, Sokka and Toph had just set up camp and the sun was setting in the sky. Katara looked at the sun and thought of the firebenders, who drew their power from the sun. She looked at the river and thought of the waterbenders, who's strength comes from the ocean. She looked at the clouds and thought of Aang, she didn't know where the airbenders got their strength or power, but she knew they got it from somwhere. She looked at the earth and remembered what Toph had told them about the badger-moles.
Katara stirred the water as she brought out an orb of it. This should be enough for the soup tonight. She thought as she headed back to the camp.
"Where have you been!" Sokka ranted. "My stomach has been complaning for the past five minutes! You know that I can't go long without any food!" Katara just shook her head. Somethings didn't need a source of power or strength, Sokka's stomach didn't need either, it was always empty and Sokka made enough of a fuss about it to annoy the rest of the camp for at least another century. Katara giggled into the palm of her hand at that last thought.