Depression increases your risk of a number of diseases and other conditions by, for example, increasing levels of stress hormones such as cortisol or adrenaline. Depression can affect the immune system, making it harder for your body to fight infection. Vaccinations are even less effective in people with depression.
The total surface area of the Earth is about 7008510000000000000â 510 million km2 (197 million sq mi). Of this, 70.8%, or 7008361130000000000â 361.13 million km2 (139.43 million sq mi), is below sea level and covered by ocean water.
View full size image. No matter how many continents you count (the old-school way teaches seven, while new methods have six) the biggest of them all is Asia. It spans 17,139,445 square miles â 29.1 percent of Earthâs total land mass â and has a population of 4.1 billion people. The other commonly recognized continents are Africa, Europe, North America, South America, Antarctica, and Australia.