railway RRB JE (CBT I + CBT II) Mock Test 2024 General Knowledge Ecology and Environment Environmental pollution
Consider the following:
1. Aerosols
2. Foam agents
3. Fire retardants
4. Lubricants
In the making of how many of the above are hydrofluorocarbons used?
1
Only one
2
Only two
3
Only three
4
All four