There is one mistake in each sentence. Find and correct it

1. In 2050, the world's population will grown to 9 billion
--> will grow

2. Traffic congestion has become a serious problem in big cities, doesn't it?
-->  hasn't

3. The amount of motorbikes should be limited to reduce traffic jams
-->  number

4. Forest areas are destroy to make space for new house.
-->  destroyed

5. Less than thirty children each year develop the disease.
--> Fewer 

6. Nearly one million people live in Dharavi, the largest slum of Mumbai.
--> in

7. There are social cause of homeless, such as a lack of housing, poverty, and unemployment
--> causes

8. Your father used to drink coffee every morning, usedn't he?
--> didn't