Why is there a height gap between southerners and northerners?

First, because of the cold weather in the north, when the ratio of surface area to volume is high, it is relatively small and easy to keep warm. Therefore, after long-term screening by nature, people who stay in Bao Bei are taller. It is hot in the south, with short surface area and large volume ratio, which is easy to dissipate heat.

Second, because the nutritional value of staple foods such as rice eaten in the south is lower than that of pasta in the north.

Third, because of the heat in the south, people fall asleep late, which is not conducive to the secretion of growth hormone.

Fourth, cold weather will prolong the growth cycle of human body, while wet weather is not conducive to bone development.