Of the six orders of Pulmonata, two â the Onchidiacea and Soleolifera â solely comprise slugs. A third family, the Sigmurethra, contains various clades of snails, semi-slugs (i.e. snails whose shells are too small for them to retract fully into) and slugs. The taxonomy of this group is in the process of being revised in light of DNA sequencing.
Q: How much of the worldâs oil reserves are located in OPEC countries? A: 80% of the world's oil reserves are located in just 13 countries which make up OPEC (the Organization of the Petroleum Exporting Countries). Algeria, Venezuela, Saudi Arabia, Iran, Iraq, Kuwait, Angola, Indonesia, Ecuador, Libya, Nigeria, Qatar, and the United Arab Emirates.
Most existing oil platforms have been installed in shallow water, but the trend is toward deeper and deeper installations. Worldâs Deepest Oil Development. The deepest floating oil rig is the Perdido oil rig operated by Shell Oil Company in the Gulf of Mexico about 200 miles south of Galveston, Texas. The Perdido fold belt is one of the larger discoveries of crude oil and natural gas and the field lies under nearly 8,000 feet (2450m) of ocean.