Instead of a D and R, WhatsApp uses checkmarks to represent message status. Based on the precedent set by BBM and WhatsApp, I think a LOT of WhatsApp users out there mistakenly take this to mean that one checkmark means the message has reached the phone while the second checkmark means the message has been read.
Food is scarce and the climate is very cold. Many animals have adapted to survive the bitter cold. Animal life on mountains vary from continent to continent. The animals in the mountains of North America (Canada, USA) include the big horn sheep, mountain goats, brown bear, black bear, grizzly bear, mountain lions and antelope. Further information
Mountain ecosystem: Mountain ecosystem, complex of living organisms in mountainous areas. Mountain lands provide a scattered but diverse array of habitats in which a large range of plants and animals can be found. At higher altitudes harsh environmental conditions generally prevail, and a treeless alpine vegetation, upon which the present account is focused, is supported.