1.2 Consider a peptide chain of 4 monomers. Two monomers at the ends are of type A and the two in the middle are of type B. For simplicity, imagine that the peptide lives on a two-dimensional lattice with each monomer occupying one lattice cite. As a "toy" model, we consider the peptide "folded" when the two A monomers are next to each other (in adjacent cites of the lattice). How many total configurations can the chain attain on the lattice? What is the probability of each configuration if there are no interactions either between A or B monomers? What is the probability that the peptide is "folded