Suppose $X=\cup K_n$ is a topological space, $K_n$ is a metrizable subspace in $X$ for every $n \in \omega$, then $X$ is a metrizable space?
In metrizable spacespaces, compactness is equivalent to $\sigma$-compactness?
One more: Is pseudocompactness hereditary with respect to $\sigma$-compact subspace?

