What would the world be like if everyone became a dwarf?

First, everything is getting bigger, second, it is difficult to survive, and third, it is not easy to get hurt. 1 The smaller the person, the larger the relative object. In fact, these projects have not changed. Because people become smaller, they are easily hurt by other animals and plants, and are also greatly affected by the weather. 3 people become smaller, that is, the volume becomes smaller and the weight becomes lighter (under the condition of constant density), and the impact damage is smaller. My inference should be correct.