I add about 1/2 cup of baking soda to every load of laundry. We have pretty hard water. The baking soda softens it so that it is more effective at washing away the detergent. Been doing this for a couple of years and I have noticed that our towels don't lose absorbency like towels we've had in the past.
The average number of children each woman will have over the course of her lifetime is called the Fertility Rate In 2011, the overall global life expectancy for both men and women was
The net reproductive rate R0 is the number of offspring an individual is expected to produce during its lifetime (a net reproductive rate of 1 means that the population is at its demographic equilibrium). This definition envisions the generation time as a renewal time of the population.