PART A
Answer: The use of imagery emphasizes how important the boycott is to the people of South Africa, persuading Kumalo to join the boycott.
Explanation: The speaker expresses the importance of the boycott by using imagery - he describes women, children, and ill people fighting for a cause in terrible conditions. The imagery is meant to persuade Kumalo to join the boycott because the speaker states, "I cannot stop you taking a bus, umfundisi, but this is a cause to fight for".
PART B
Answer: Kumalo's tears at witnessing such cooperation indicates that he is not used to seeing people of different races work together.
Explanation: Kumalo was a political activist who fought against racial injustice. To see both races working together gave him hope for a more equitable society.