High school geography questions, about dichotomy, online, etc!

Looking at the noon sun height, the highest day of the year in the northern hemisphere is the summer solstice, the lowest is the winter solstice, and the sun height is the average of the highest and lowest at the vernal equinox. It is the vernal equinox that makes the noon sun longer. Judging from the length of day and night, the longest day in the northern hemisphere is the summer solstice, and the shortest is the winter solstice, and the day and night are equally divided. It is the vernal equinox that makes the days gradually longer. A shortened autumnal equinox.