Codon Codon is a combination of three successive nucleotides in a DNA or RNA strand. All the nucleic acids, DNA and RNA, have nucleotides sequenced as a set of codons. Each nucleotide consists of a nitrogenous base, one of A, C, T/U, or G.
Phases of the moon are simply how much sun is hitting the surface of the moon, with the moon being between the earth and the sun. Lunar eclipses occur when a conjunction between the earth and the sun... with the earth casting a shadow on the full moon.
Now, if you read the section above on the phases of the Moon, you might think that a lunar eclipse would occur every time there was a Full Moon (since the Moon is on the shadow side of the Earth during Full Moons). However, the orbits of the Earth around the Sun and the Moon around the Earth are not on the same plane.