12. There are seven types of renewable energy.
 How many types of renewable energy are there?
13. Solar panels will be placed on the roofs of houses and buildings.
Where will solar panels be placed?
14. Children living in slums have more diseases because of poor living conditions.
Why do children living in slums have more diseases?
15. Overcrowding causes problems such as housing, congestion, unemployment, etc.
What does overcrowding cause?

12, How many types of renewable energy are there?
13, Where will solar panels be placed?
14,Why do children living in slums have more diseases?
15, What does overcrowding cause?