Please someone help me

Which pronoun has an unclear antecedent in the following sentences? the sixth-grade students liked volunteering their time to read to the elderly people in the hospital. it made them happy. a. their b. it c. them d. no unclear antecedents

What effect did increased automobile production have on other industries

In a study, people were asked to imagine simple occasions that made them happy and to remember events that made them feel proud about themselves. it was observed that the subjects developed an increasingly positive attitude. these changes are known to be healthy, leading to greater physical activity and reducing unhealthy habits. based on this excerpt, we can conclude that a positive attitude .