Researchers would like to determine history of car crashes a…

Researchers would like to determine history of car crashes at the University of Wisconsin Stevens Point.  They suspect, based on insurance claim data, that male students will have higher rates of crashes than female students.  To account for this, they are first dividing the UWSP population by gender and then randomly selecting 200 women and 200 men for the survey.  What type of sampling is this? 

On which massive ancient structure were the workers instruct…

On which massive ancient structure were the workers instructed to finish the stone at the quarry, and transport it in, so that no hammer or chisel or any iron tool was heard in the temple while it was being built; and that the stone blocks had to fit together perfectly, as no mortar or clamps would be used to hold the stones in place?