In this Tuesday, March 12, 2019 photo students from the Theodore T. Alexander Science Center School practice brushing dog&#8217;s teeth at an interactive display during a preview of an exhibition called &#8220;Dogs! A Science Tail&#8221; at the California Science Center in Los Angeles. The new exhibit that opens Saturday examines the relationship between dogs and humans and explores why the two species seem to think so much alike and get along so well.  (AP Photo/Richard Vogel)