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.
In findings published today in the Marine Ecology Progress Series, researchers have found that ocean currents may explain why the Indo-Pacific lionfish Pterois volitans living in the Atlantic is yet to make its way to Brazil.