He asked: 'Who are the three gods?' Yagnavalkya replied: 'These three worlds, for in them all these gods exist.' He asked: 'Who are the two gods?' Yagnavalkya replied: 'Food and breath.' He asked: 'Who is the one god and a half?' Yagnavalkya replied: 'He that blows.'

In plain words: Yagnavalkya says the three gods are the three worlds, because all the gods live in them. The two gods are food and breath. The "one and a half" god is the wind that blows.