The major reason for using U. S. government documents as secondary data sources is that they .

The correct answer to this open question is the following.

Although you did not include options for this question, we can answer the following.

The major reason for using U.S. government documents as secondary data sources is that they are detailed, complete, and consistent.

The United States government documents are a trustful source of information because these have been validated by experts, historians, researchers, and scholars. That is why we can trust them.

They are supported by other documents, references, interviews, and testimonies. The criterion to evaluate secondary data as an accurate source of information invite scholars and historians to evaluate the date of the data collected.

the correct labels are as follows:

a: yellow river

b: himalayan mountains

c: north china plain

d: taklimakan desert