The right answer is Troposphere. The troposphere is one of the layers of the earth's atmosphere, is in contact with the surface of the earth and has a thick between 7 and 17 km. In this layer is where meteorological phenomena such as winds, rain, and snow are formed, and this is where the highest concentration of oxygen is found, therefore this atmospheric layer is vital for the life of the planet.
I hope this answer can help you.
