What are the strengths and limitations of probability and non-probability sampling?

1. could you please brief answer on the below questions:
– What are the differences between a census and a sample?
– What are the strengths and limitations of probability and non-probability sampling?
– How does secondary data differ from primary data?
– What are the strengths and limitations of secondary data?
2. 250 words are enough
3. please add a question to continue a discussion