When independent variables cannot be manipulated for one reason or another, ____________ research is often used

How much distilled water must be mixed with alcohol 70% to prepare 32 oz of alcohol 32%?

A) 14.6 mL B) 17.4 mL C) 438.9 mL D) 521.1 mL

Tetanus is most likely to occur with a/an ____

A) laceration B) incision C) amputation D) puncture