Which statement identifies the central idea of the text? a.)scientists know more about the biological functions of yawning than why some social species “catch” yawns from each other. b.)scientists believe that dogs are more likely to engage in contagious yawning because they are more empathetic than most humans. c.)while scientists do not know what causes yawning, they have found that people who yawn more frequently are often mentally and physically healthier. d.)while scientists have limited knowledge about why we yawn, studies have shown that people and animals can “catch” yawns from social interactions.