(2) march 21: celestial equator; june 21st ;Tropic of Cancer september 23rd; celestial equator; December 23rd: the Tropic of Capricorn
(3) <u>in a leap year, we add an extra day in February </u><u><em>(making it 29 days instead of 28)</em></u><u>. What goes around: The reason we have February 29 every four years is because of two different time cycles involved with the rotation of the Earth.</u>