What tool could you use to organize and illustrate the structure of a given population demographic?
a)
data flow diagram
b)
entity-relationship model (e-r model)
c)
population density equation
d)
data structure diagram (dsd)

Option (d)

Explanation:

The tool could you use to help organize and illustrate the structure of a given population demographic is Data Structure Diagram.  It uses graphical ways to represent the age distribution, sex ratio of the given population.  

Changes can be made in the Composition of the population, Educational attainment, occupation like all types of Information can be organised in a format. Also population pyramid charts can be implemented for clear overview.

the first phase of the government’s plan for settlement was building the transcontinental railroad. the railroad provided a way to bring settlers and manufactured goods west and ship their agricultural and mining produce east. the transcontinental railroad was an essential artery for rapid development of the frontier.

the second phase of the government’s plan was a liberal land distribution policy that made it possible for many people to homestead. with these two key elements—transportation and cheap land—the government rapidly achieved its goal of persuading people to move west, settle on farms, and push back the frontier.

i i think it might b c