Or, for a medical example, suppose smoking multiplies the risk of lung cancer by some number R: then the Wald test can be used to test whether R = 1 (i.e. there is no effect of smoking) or is greater (or less) than 1 (i.e. smoking alters risk).
There are more than 900 species of Tardigrade or Water Bear, pictured. They're found everywhere in the world, from the highest mountains to the deepest oceans. Boil the 1mm creatures, freeze them, dry them, expose them to radiation and they're so resilient they'll still be alive 200 years later.
Polar bears are found across the Arctic. They are most abundant in areas with annual sea ice and productive ringed seal populations. There are five nations with polar bears: U.S. (Alaska), Canada, Russia, Greenland (Kingdom of Denmark), and Norway (Svalbard). Polar bears do not live in Antarctica.hile short by our standards, polar bears are considered long-lived animals. In the wild, polar bears live an average 15 to 18 years, although biologists have tagged a few bears in their early 30s. In captivity, some long-lived bears reach their mid-to late 30s.