What is the purity standard for oxygen?

What is the purpose of prerinsing or presoaking instruments after use?

a. To prevent blood and debris from drying on instruments b. To prevent the instruments from rusting c. To soften and remove dried blood and debris d. To eliminate the need for cleaning them before sterilization

The "T" in the mnemonic OPQRST refers to the:

A) duration of symptoms. B) patient's condition. C) treatment plan. D) trauma the patient has experienced.