Final answer:
The Birth Rate is the concept that measures the number of people being added to a population through birth, with a positive difference between birth and death rates indicating population growth.
Step-by-step explanation:
The concept defined as the measure of the number of people being added to a given population through birth is the Birth Rate. This figure is typically expressed in the number of births per 1,000 people per year. For a country that has a birth rate of 35 per 1,000 people and a death rate of 15 per 1,000 people per year, the net number of people added to the population each year per 1,000 people is 20 (35 births - 15 deaths). This is calculated by subtracting the death rate from the birth rate. To find the rate of growth in percent, we take the net people added per 1,000 people (20) and divide by the total population per 1,000 (which is 1,000), then multiply by 100 to get the percentage, resulting in a 2% rate of growth.