Quotation marks, also called 'inverted commas', are of two types: single and double. British practice is normally to enclose quoted matter between single quotation marks, and to use double quotation marks for a quotation within a quotation:
The oceans absorb the sun's heat, transferring it to the atmosphere and distributing it around the world via the ever-moving ocean currents. This drives global weather patterns and acts as a heater in the winter and an air conditioner in the summer.
Knowledge of ocean currents is also extremely important for marine operations involving navigation, search and rescue at sea, and the dispersal of pollutants. It is quite evident from observations of ocean flow that the wind moves water, and that the wind is one of the primary forces that drive ocean currents. In the early part of the 20th century, a Norwegian scientist, Fridtjof Nanson, noted that icebergs in the North Atlantic moved to the right of the wind.