a) The answer is 0.1/year.
The reproductive rate for the population can be expressed as:
(number of births - number of deaths)/number of individuals = (55-5)/500 = 50/500 = 0.1
b) The answer is exponential growth.
The exponential type of population growth occurs when resources are unlimited. When there are no limiting factors, population exhibits exponential growth. If every year population has mentioned reproductive rate, that means it is not limited by any factor (food, space, etc.). Thus, it must be exponential growth.