Answer:
Concrete noun is a noun that we can hear, see, smell, touch, and taste, so it is interacted in a physical way through our senses. For example, house, tree, bottle…
On the other hand, abstract noun exists only in our mind; it cannot be touched, seen, or tasted. Abstract nouns refers to feelings, emotions, qualities, concerns… For example, love, freedom…
In this sentence, girl, brother, volcano are concrete nouns, but courage is an abstract noun.
