Answer:
Adjective Phrase is 'string of pearls'
Modified Noun is 'string'
Step-by-step explanation:
An adjective phrase is a phrase in which the word starting the phrase is an adjective.
A modified noun is a noun which modifies another noun which follows it. Noun as a modifier provides with specific information about the noun in the sentence. In the above sentence, the adjective phrase is 'string of pearls' and the modified noun is 'string'.