Answer:
(b) Volcanic eruptions
Explanation:
Volcanic eruption is naturally occurring event. In Volcanic eruptions many toxic gases are released into the atmosphere such as carbondioxide, carbonmonoxide, hydrogen sulfide, hydrochloric acid and Sulphur dioxide etc. These toxic gases goes to the atmosphere and combine with water vapours forming the water acidic. When this acidic water comes to the earth surface, skin and valuable stones are damaged from it.
