11. Consider the following statements about Hydrogen sulfide
1- Hydrogen sulfide (also known as H2S, sewer gas, swamp gas, stink damp, and sour damp) is a colorless gas known for its pungent “rotten egg” odor at low concentrations
2- It is extremely flammable and highly toxic.
3- It only occurs naturally in sewers, manure pits, well water, oil and gas wells, and volcanoes.
Which of the following given above is/are correct