Vào ngày hạ chí ánh sáng mặt trời chiều vuông góc ở chí tuyến bắc, tại sao ngày đó lại chưa phải là ngày nón nhất trong năm ở nửa cầu bắc

Due to time required for warmup of land and water.

Explanation:

The hottest day of the year in the northern hemisphere don't fall on the summer solstice i.e. June 21, because the ground and water in the Northern Hemisphere needs time to warm up. It takes 3 weeks or one month to warm up the land and water, once it warm up the hottest day of the year started. so the hottest day of the year in the northern hemisphere comes in the month of July.

the europeans in the caribbean colonies had to turn to africans to replace the native peoples as slave it would be letter a