We only see the Moon because sunlight reflects back to us from its surface. During the course of a month, the Moon circles once around the Earth. If we could magically look down on our solar system, we would see that the half of the Moon facing the Sun is always lit. But the lit side does not always face the Earth!
The plants absorb the nitrogen from the atmosphere and it transports down into the soil where the nitrogen-fixed bactera changes the form of the nitogen:)
