Which relationship is always true for the angles x, y, and z of triangle ABC? x+z=y
y+z=x
x+y+z=180 degrees
x+y+z=90 degrees

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.