Let \(M\) be a manifold with boundary. Show that if \(M\) is orientable then \(\partial M\) is
orientable.
Let \(M\) be an \(n\)-dimensional manifold and \(N\subset M\) an \(n-1\) dimensional submanifold such
that \(N\) has a neighborhood \(U\subset M\) with \(U\) homeomorphic to \(N\times (0,1)\). Show that if \(M\) is
orientable then \(N\) is orientable.