Line chosen from the poem is fair as a star has use of simile.
Step-by-step explanation:
Four lines chosen from the poem are :
A violet from a mossy stone
half hidden from the eye!
Fair as a star, when only one
Is shining in the sky.
In the third line of this stanza, simile has been used because a comparison has been made in the poem using the word "as". This helps to understand the meaning that the poet is trying to make with more impact and gives them an example.