What percent of all species that ever existed do biologists estimate are now extinct? A) 25%

C) 50%

D) 75%

B) 5%

E) 99%

In the northern hemisphere what is the direction of the surface wind circulation in a high pressure system

Suppose you are making a map of stars around the sun, and you draw earth 1 cm from the sun on your map. the brightest star in the night sky is 8.6 light-years from the sun. on your map, how far would you place that star from the sun?

What is tge speed of sound in dry air at 0°c