Petroleum was formed from organisms: (a) living on the land (b) living on the plants (c) living in the sea (d) living on the rocks.
(c) living in the sea
Petroleum is formed from dead organic matter. When a large amount of dead organism, usually zooplankton and algae are buried underneath sedimentary rock and subjected to intense heat and pressure, after such a process the molecule turn into petroleum. Zooplankton is organism found in ocean and seas. Over millions of years, absence of air, high temperature and high pressure transformed the dead organisms into petroleum and natural gas.