On a hot day, a concrete sidewalk feels hotter than the water in a small swimming pool. And a sandy beach feels hotter than the lake or ocean. What do these observations tell you about temperature changes when different materials are heated?

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.