How does a season, an equinox, and a solstice related

Why is it important to reduce the number of chromosomes in half when forming gametes for sexual reproduction?

Amale bird-of-paradise uses a dance to attract mates in which it flaps its tail feathers on the ground and jumps around a potential female mate. a different male bird-of-paradise does a similar dance but it jumps around the female in the opposite direction. the female bird is only attracted to one style of dance, in one direction. this is an example of speciation.

Classify the structures as homologous or analogous, depending on their structure and function.