Answer:
a. common knowledge
b. needs to be cited
c. common knowledge
d. needs to be cited
e. common knowledge
Step-by-step explanation:
a. Within the field, it should be already known.
b. We don't know who those experts are, so we need citation
c. If the audience is Canadian, for example, this would be common knowledge.
d. Although Charles Darwin is known, the date of his birth is not necessarily common knowledge.
e. It is common knowledge who has won the Nobel Prize.