What is the U.S. Food and Drug Administration (FDA) purity standard for O2?

Birefringence can be detected by which of the following?

A) Electron microscopy B) Bright field microcopy C) Polarized microscopy D) Dark field microcopy

Entering commands on the computer keyboard instead of using the mouse as a pointer is an effective way to prevent repetitive movement injuries (RMIs)

a. True b. False Indicate whether the statement is true or false