What's the correct genitive construction of heart and function?
Should it be "heart's function" or "heart function"?
"The heart function is to supply blood to whole body."
"The "heart's function" is to supply blood to whole body."
By googleing I found both choices, and that's why I'm not sure about it. Please, it would be very useful if you explain your answer, because I find my self in such situation very often about other words as well.