C. Atmosphere - which is the one sphere that means "air" or "gasses". The other ones mean, Biosphere = "living", Lithosphere = "land", and Hydrosphere = "water"
The seafloor spreading occurs at the mid-ocean ridges. The reason for this is that the convection currents from the mantle manage to break through the oceanic crust and propel magma on the seafloor. As they do, the magma consolidated in the water and new crust is created. Since there's constant pilling up of new crust, it pushes the old crust away in both sides. This results in the movement of the plates, and as they move eventually they will come into a situation to collide, resulting in the continents to start merging with one another. As the continental masses merge, they will gradually create a supercontinent.
Latitude affects climate because the closer you are to the equator, the warmer the temperature is. Altitude affects climate because the higher up you are, the closer you are to the sun, the warmer it is. Prevailing winds affect climate because wind speeds up and brings moisture and precipitation.