Final answer:
The second sentence needs the noun 'heads' to be plural to match 'parents', and the third sentence requires 'novelists' to be plural to agree with the two individuals named.
Step-by-step explanation:
The student is asking for help with identifying nouns that do not agree in number in given sentences and how to revise them for agreement. Here are the corrections:
- The sentence is correct as written; all nouns agree in number.
- 'Both her parents...shook their heads in disbelief when she rejected the suitor.' - The correct noun should be 'heads' since 'parents' is plural.
- 'Chinua Achebe and Chimamanda Ngozi Adichie both became well known by worldwide audiences as Nigerian novelists.' - The noun 'novelist' should be plural 'novelists' to agree with the plural subject.