Explanation Text 
The Definition
Explanation is a text which tells processes relating to forming of natural, social, scientific and cultural phenomena. Explanation text is to say ‘why’ and ‘how’ of the forming of the phenomena. It is often found in science, geography and history text books.
Generic Structure
Sequenced explanation
Closing
General statement
Stating a series of steps which explain the phenomena.
Actually this is not mentioned in explanation text, however, many people think that the last of paragraph is clossing, in which it is actually part of sequenced explanation
Language Features
The title examples of the text
How Chocolate is Made
How a Cancer is Formed
How does Rain Happen?
How a Plane Flies
Stating the phenomenon issues which are to be explained.
Why Eiffel Tower was Built
Using abstract noun (no visible noun)
Using Passive voice
Using Action verbs
Using simple present tense
Containing explanation of the process