The surface \(M_g\) of genus \(g\), embedded in \(\mathbb {R}^3\) in the standard way, bounds a compact region \(R\). Two copies of \(R\), glued together by the identity map between their boundary surfaces \(M_g\), form a closed 3-manifold \(X\). Compute the homology groups of \(X\) via the Mayer-Vietoris sequence for this decomposition of \(X\) into two copies of \(R\).
Diagram: a standard embedded genus \(g\) surface, drawn schematically as a handled surface bounding a compact region \(R\).