As a country progresses from the preindustrial stage to the postindustrial stage, what will happen to the birth rate and death rate?

Both birth rate and death rate will decrease.

Explanation:

Demographic transition: The process whereby a country moves from high birth and death rates to relatively low birth and death rates.

The decline in death rate is due to better economic and social conditions of the country which leads to control of pre-existing diseases, better medical facilities,more food production,increased jobs,better sanitation and hence better quality of life.

Decline in birth rate is due to improved quality of life and also could be due to availability of family planning services in highly developed countries.Moreover access to education especially in female population has created awareness regarding birth control.

where is the scientific experiment?

the dna molecules have a negative charge because of the phosphate groups in their sugar-phosphate backbone, so they start moving through the matrix of the gel towards the positive pole. power is turned on and dna fragments migrate through gel (towards the positive electrode).

explanation: