Developmental science is a field of study devoted to select one:

a. proving contemporary theories of development.

b. proving contemporary theories of development.

c. understanding constancy and change throughout the lifespan.

d. identifying genetic contributions to disease and illness.

I believe the answer is: c understanding constancy and change throughout the lifespan.

In social settings, developmental science research is being done by observing the change that the subjects experience if being put at a certain time of environment over time. Example of its research would be finding out whether there is a correlation between parents income with performance throughout school years.