Read the sentence. The scientists had a theory to explain the unusual relationships in their discovery. Which underlined word is a concrete noun?

A) relationships

B) scientists

C) discovery

D) theory

The correct answer is B.

The scientists had a theory to explain the unusual relationships in their discovery.

Explanation:

Concrete nouns mean things that can be seen and touched. For example, "the Cat is lying on the grass", Cat is the Concrete noun, "the Gate prevents a lot from coming in". Other examples include, Spoon, Bag, Cloth, Car, Chair, book, etc.

Given the above, the appropriate answer is Scientists because it can be seen.