The examples explained

1. Lincoln began his famous speech at Gettysburg with the line “four score and seven years ago…”

Requires acknowledgment -- any quotation requires citation of the source.

2. The famine in Ireland was responsible for misery and death wherever the potato blight (phytophthora infestans) grew.

Requires acknowledgement -- the information is not widely known and must be cited.

3. Hugo Chavez is currently President of Argentina.

Does not require acknowledgement -- This information is available in many sources and does not have to be cited.

4. 82% of students surveyed admitted lying to their parents.

Requires acknowledgement -- statistical information taken from a source must be cited.

5. The main staple for pandas is bamboo.

Does not require acknowledgement -- the information can be found in many reference books.

6. Heavily invested in burning fossil fuels, in 2005 the United States was the largest single producer of carbon dioxide, which contributes to global warming.

Requires acknowledgement -- all statistics need citation.

7. Although some people think you can get a wart from holding toad, this is really a myth.

Requires acknowledgment -- because it goes against commonly held beliefs, it needs a citation.

8. Lynard Skynard was notorious for tearing up hotel rooms and wreaking havoc whenever they went on tour.

Does not requirement acknowledgement -- this information is widely known, as suggested by the word notorious.

9. University of Michigan has produced more high quality quarterbacks than any other college football program.

Requires acknowledgement -- because this is a controversial opinion, it needs to be cited.

10. We observed that the air temperature on the Severn River is at least three degrees cooler than on the nearby shore.

Does not require acknowledgement -- personal observations do not require acknowledgment.