Let $m_G$ denote the number of perfect matchings graph $G$. We introduce a combinatorial tools for determining parity and giving lower bound on power 2 dividing $m_G$. In particular, we certain vertex sets called channels, which correspond to elements in kernel adjacency matrix $G$ modulo $2$. A result Lov\'asz states that existence nontrivial channel is equivalent being even. give new proof th...