What purpose does pyruvate serve in cellular respirations

In order to survive, all the cells in your body need energy. ... To provide this energy, your cells must break down the glucose in your food during a process called glycolysis and convert it into pyruvate, sometimes called pyruvic acid, and the molecule that feeds the Krebs cycle, our second step in cellular respiration.

No because the eaeht is on a 23.5 degree axis tilt and so when it is winter the northern hemisphere is pointing away from the sun and the soutubern hemisphere is pointing toward the sun