Which gas has a much lower concentration on Earth compared to Mars and Venus due to the process of photosynthesis

The primary agent of contact metamorphism is

What is the general rule about surface currents? cold water flows along the ocean floor towards the equator. the east coasts of continents have cold surface currents, and the west coasts of continents have warm surface currents. seasonal and constant offshore winds create significant upwelling along the west coasts of south and north america and africa. the west coasts of continents have cold surface currents, and the east coasts of continents have warm surface currents.

When you start from a given set of rules and conditions and determine what must be true you are using blank reasoning