Freeing of individual enslaved persons took place very rarely in the United States, although it tended to happen when slaves reached a certain age, or when relatively compassionate slave-owners wanted to reunite slave families.
This sentence technically doesn't contain an error in verb-noun agreement, however the noun "each one" is odd here. It should be "everyone"
I would love to help you but you have to let me know what book the questions are asking about.
Answer:
The Communal Award, announced by Ramsay MacDonald on 16 August 1932, ensured the retention of separate electorates for Muslims, Sikhs and Europeans, and considerably increased the limited number of provinces that offered, under the Government of India Act of 1919
