What is one way for detecting bias in a written source?

In what way did expansion and global trade during the 15th to 18th centuries affect the economies of european countries?

"if i have seen farther than others," said newton, "it is because i have stood on the shoulders of giants." who were the giants to whom newton was referring? could this be said of any scientific accomplishment? explain.

What types of subjects did public high schools in the 1900s emphasize and why