Why does population composition matter?

Eastern europe and parts of northern europe have which of the following climates?

You have been tasked with sorting the rock samples shown into three categories, with two rocks in each category. what attribute would you use to sort these rocks? which rocks would be in each category? rocks: obsidian, coquina limestone, granite, soapstone,pumice, and gneiss.

In which direction does the moving force of air flow? a-from warm temperatures to cold temperatures b-to areas of high pressure to areas of low pressure c-east to west d-from high elevations to low elevations