1. Who invented Helicopter ?

Answer:

Igor Sikorsky

2. Who invented paper ?

Answer:

Cai Lun

3. Who invented Automatic rifle ?

Answer: John Browning of U.S.A. in 1918.

4. Who invented HIV ?

Answer:

5. Who invented Vitamin D ?

Answer:

Edward Mellanby discovered Vitamin D while researching a disease called rickets in 1922

6. Who invented Diesel Engine ?

Answer: Rudoff Diesel of Germany in 1895

7. Who invented Gramophone ?

Answer:

Emile Berliner in 1887.