Consider the pullback of a (Hurewicz) fibration p:E-->B$p\colon E \longrightarrow B$ along any map f$f$ and let p'$p'$ denote the base change of p$p$ in the pullback. Suppose that H_(p), the induced homomorphism in singular homology (with coefficients in any field) of p, is surjective . Is it true that H_$H_*(p)$, the induced homomorphism in singular homology (p'with coefficients in any field) of $p$, is surjective . Is it true that $H_*(p')$ is also surjective? If not, when is this possible?