How are the diffusion of language and religion different?

How is this a question? where are the answer choices?

Most topographic maps, the index contour lines are generally darker and are marked with their elevations. 

Airplanes usually fly in the lower part of the stratosphere - there is nearly no water vapor and it's very dry, so it to avoid big turbulences. it's about 8-10 kilometers above ground (depending on weather conditions, region etc.)