Modern birds have feathers and can fly. when paleontologists discovered a fossil of archaeopteryx, a dinosaur with feathers, they suggested perhaps it could fly. what big idea in biology did they apply in this situation?

Cpr, or cardiopulmonary resuscitation, is a first-aid technique to save lives. it involves compressions of the patient's chest cavity. which description is the best description of the functions of chest compressions in cpr? chest compressions are done to pump the heart. chest compressions are done to strengthen the rib bones. chest compressions increase carbon dioxide inhalation. chest compressions allow the patient's muscles to wake up.