C. hydrogen
Hydrogen is an element, while salt (sodium chloride), protein (which is made up of amino acids), and insulin (a specific protein hormone) are all compounds or complex substances made up of multiple elements.
A. salt
B. protein
C. hydrogen
D. insulin
1 answer
C. hydrogen
Hydrogen is an element, while salt (sodium chloride), protein (which is made up of amino acids), and insulin (a specific protein hormone) are all compounds or complex substances made up of multiple elements.