Questions

Nouns form the largest word class, and verbs the second-largest in English.

The Sahara is the biggest desert in the world.

It occupies the northern one third of the African continent.

The size of the pupil of the automatically adjusts itself according to the intensity of light passing through it; if the intensity is more, the size is less, if less, it is more. So in our case the pupil should dilate i.e , increase in size to be able to see in the dark. This switchover takes some time. But here the entry into the dark room is immediate. So the eye has no time to adjust itself and hence is not able to see at all for a while. 

Lee Falk

Most important weather phenomena occur in the layer of Thermosphere.

Most of the weather phenomenon occur in the layer of Troposphere.