In which medium is the speed of the sound with the greatest? Air in the classroom. Iron railroad track. Pool of water. Vacuum in space.?

Explain the teachings of surah al fatiha

Iknow this isn't a question, but is there someway to ask a question under public safety or is there no category for it? i don't know if i'm overlooking it or not.

Arecipe calls for 2 cups of flour to make a cake. you look in the stock room and see a bag of flour that has a tag that says this bag contains 25 cups of flour. how many complete cakes could you make from this bag of flour?