They can also be derived from petroleum sources, though, or made in the laboratory. (annmariegianni.com)
The most productive coastal upwelling area of the modern ocean is the Benguela upwelling system off south - western Africa, an area that is considered to represent an important modern analogue of petroleum source rocks deposited in the geological past. (phys.org)
Conventional carpet pads are made of foam and synthetic rubber made from nonrenewable petroleum sources. (believemidwiferyservices.com)