In this sentence is action a noun?

If it isn't is there any others except soldiers?

Later she helped find soldiers who wher missing in action.

Yes, "action" is a noun. "were missing" is a verb. The clause "who were missing in action" is an adjective describing soldiers.

underline all the nouns in the sentence

The missionary family sailed across the ocean to their new home.

please help me like asap

Sure! I'll be happy to help you right away.

To identify the nouns in the sentence, we need to look for words that represent people, places, things, or ideas. Here are the nouns in the sentence you provided:

- missionary
- family
- ocean
- home

Please note that "the" is an article and does not function as a noun.