Answer
a) Higher incomes in a society would increase the demand for healthcare. In turn, the demand for healthcare would increase, and there would be a higher need for more healthcare workers (increasing the wages paid to healthcare workers).
b) Better healthcare outcomes would increase the overall societal well being, and in turn, this would likely increase how long people work. If people work longer, they are likely to have increased incomes in the society.
Work Step by Step
c) If the first hypothesis is true, then healthcare would be just consumption (and not investment). However, if the second hypothesis is true, then healthcare is more of an investment in society than consumption by society.