What do we learn from "ha'Kol Holech El Makom Echad"?
Rav Sadya Gaon, Metzudas David: It is like the verse concludes - everything comes from earth, and returns to earth. Ibn Ezra - this explains the previous verse. All is Hevel, for all goes to the same place!
What came from earth, and returns to earth?
Rashbam, Ri Kara: Both people and animals.
R. Avigdor: Everything in Shamayim was created from Shamayim, and everything on the land was created from the land, except for man - his [body's] creation was from the land, and his Ru'ach and Neshamah are from Shamayim.
Metzudas David: The formation of Adam ha'Rishon and all living beings [in the six days of creation] from earth, and all return to earth when they die.