What is one main characteristic of secondary sources intended for academics and students?
A. They include interesting events and characters to entertain the audience.
B. They include drawings and maps to illustrate the work.
C. They include a bibliography and citations to credit the sources.
D.
They include URLs for websites and blogs to support the arguments.

The correct answer is letter C

Secondary research, or “documentary research”, is the synthesis of information and data that has already been collected by other sources. Magazines, books, import and export data, production data, statistics and government censuses are some examples of secondary research.

Meaningful research must produce at least one formal publication. Throughout the research process, documents are produced, also called “sources”, which can be classified into: first-hand (or primary) sources, second-hand (or secondary) sources and tertiary sources.

the causes of the dust bowls were severe droughts,   lands became dry and hard, temperature was higher than usual, hot and dry conditions killed crops, high winds. because of those factors, the winds kicked up dry soil and created clouds of dust.