premise: a new moon is a kind of phase of the moon sent2: a student cannot observe the moon in the clear night sky on feburary 21 sent3: a moon phase occurs 28 days after the last time it occurred sent4: the new moon is when the dark half of the moon faces the earth sent5: the dark half of the moon is not visible sent6: 28 days after feburary 21 is march 21.
hypothesis: producers provide the most food during summer