Question

Which of the following regions are present in the night time?

(a) D and E layers

(b) E and F layers

(c) F1 and F2 layers

(d) D and F layers

Answer 1

Right option is (b) E and F layers

The best I can explain: During night time D layer is not present. F1 and F2 layers get combined to form an F layer during night time. So E and F layers are present at night time.