Answer:
He protested the practice of apartheid.
Step-by-step explanation:
Nelson Mandela was a South African who was born in a poor family, but later on became greatly involved in politics. He started protesting against the apartheid (a system that favored the segregation between the whites and the blacks) together with the other members of the African National Congress (ANC). They started with a non-violent resistance. This escalated the issue being protested and many blacks joined to protest by violating the laws. Later on, he planned on having a guerilla warfare; however, his plan was sabotaged. He was imprisoned for 27 years, but this made the activists even stronger. He was only released when the President of South Africa ended the apartheid due to international pressure in 1990.