What is the source of carbon-14 in living organisms?

Ms.ringer asked her class "what are the favorite colors of the students in our school" which student correctly deceives ms.ringer's question

What major factors play a role in global warming? 1. human activity and normal climate conditions 2. natural factors and human activity 3. normal climate conditions and abnormal human activities 4. abnormal human activities and natural factors

What are canada’s major boundaries?