A mixture of four gases exerts a total pressure of 715 mm Hg. Gases A and B each exert 110 mm Hg. Gas C exerts 450 mm Hg. What pressure is exerted by gas D?

Ascientist wants to know how individual lions within a pride interact with each other in their own environment. to do this, the scientist sedates and tags all of the lions within a pride. then, he places several remotely-controlled video cameras near the lions' den and performs an observational field study. he collects continuous video footage over the span of one year, analyzes the video, and then forms conclusions based on his observations.