Hello, you would need to say more in the first sentence, because at the moment it would not be correct. The second sentence is not correct:) You could for example say, One function of the human body is .... or The human body has many/several functions. (function - purpose/task) As human beings, we’re designed to crave sugar since it contains glucose which is essential because it’s an energy source that keeps the human body functioning. (functioning - working) I am not a teacher so maybe others will say something more;) All the best

"The function of the human body" is more correct, but may also depend on context. "Function" is a noun in this case "Functioning" is a verb Examples using both correctly: "Eye sight is a function of the human body. If you can distinguish colors, your eyes are functioning correctly."