The LEAST preferable and reliable method of selecting people to participate in a research study is:

For an AP oblique rib projection (RPO or LPO position) obtained to evaluate upper posterior rib pain,

1. a 70-80-kVp technique is used. 2. the tenth axillary rib is centered to the collimated field. 3. the patient is rotated 45 degrees away from the affected side. 4. the image is obtained after deep expiration. a. 1 and 2 only b. 1 and 4 only c. 1, 2, and 4 only d. 1, 2, 3, and 4

The cell membrane of the ________ cell contains large amounts of myelin, which insulates the axons and allows them to send nerve impulses quickly. 

Fill in the blank(s) with the appropriate word(s).