Answer:
esophag/o/gastr/o/duoden/o/scopy
esophag – word root for esophagus
gastr – word root for stomach
duoden – word root for duodenum
-scopy – suffix for visual examination
o – combining vowel used between word parts to ease pronunciation.
O is most often used as the combining vowel, so if you are stumped as to whether to use an o or a between esophag and gastr, go for the o.
Explanation:
