Which of the following sounds can typically be heard without the use of a stethoscope?

A low ETCO2 reading, as measured by capnography, would MOST likely be observed if:

A. there is an absence or decrease in the level of CO2 in the lungs. B. a patient in cardiac arrest is receiving high-quality CPR. C. an endotracheal (ET) tube is correctly placed in the trachea. D. the cells produce large amounts of CO2 and return it to the lungs.

Which of these produce tears and secrete enzymes to destroy bacteria and viruses in the eye? 

A. Extrinsic eye muscles B. Lacrimal glands C. Nasolacrimal ducts D. Orbicularis oculi E. Conjunctivas