Question

Moving higher in altitude results in:

thinner air and, thus, cooler temperatures

denser air and, thus, cooler temperatures

thinner air and, thus, warmer temperatures

denser air and, thus, warmer temperatures

Answer 1

Answer...

Thinner Air and, thus, cooler temperatures.

Explanation...

The higher you go the thinner the air gets. It's why it's hard to breathe at such altitudes. As well, it gets colder the higher you go because the air pressure decreases.