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.
Largest Countries in the World (ranked by land area) Largest Countries in the World (by land area) The largest country in the world is Russia with a land area of 16,376,870 KmÂ² (6,323,142 miÂ²), equivalent to 11% of the total world's landmass of 148,940,000 KmÂ² (57,510,000 square miles). Below is the list of the largest 20 countries and, following, the full list of all countries and dependencies ranked by land area. See also: