As defined by the U.S. Geological Survey (USGS), heavy oil is a type of crude oil characterized by an asphaltic, dense, viscous nature (similar to molasses), and its asphaltene (very large molecules ...

Cells, the basic unit of life, are surrounded by a limiting membrane called the plasma membrane. Inside cells, there are various membrane-bounded organelles, each of which has various and distinctive ...

Deep underwater, and deeper underground, scientists see surprising hints that gas and oil deposits can be replenished, filling up again, sometimes rapidly. Although it sounds too good to be true, ...