Which substance is an element that is composed of molecules? A. water (H2O)

B. methane (CH4)

C. hydrogen (H2)

D. helium (He)

What type of interaction occurs between the r groups of valine and isoleucine in a tertiary structure? view available hint(s) what type of interaction occurs between the r groups of valine and isoleucine in a tertiary structure? salt bridge disulfide bridge hydrogen bond hydrophobic interaction