Let g be a connected bipartite graph with n vertices and q

Question

Question: Let G be a connected bipartite graph with n vertices and q edges. Prove that frank(G) = q - n + 1 if and only if the toric ideal P(G) of K[G] is a complete intersection? Let G be a bipartite graph. If G is a subdivision of K₅ or a subdivision K_3,3 prove that the binomials of P(G) that correspond to primitive cycles do not form a regular sequence.