What role does the heart play in helping the circulatory system perform its functions?

Consider the last statement in the prompt: "people take such environmental factors into account in their choices when deciding where to live." do all people have a choice as to where they live? what factor plays a key role in this decision and may therefore play a large role in determining quality of life?

Why reason best illustrates why hershey and chase chose to use viruses in their experiment?

Which description provides the best objective summary of the article in the passage?