\begin{table}%t10
\caption{Final result.}
\label{conclusion}
%\centering
\small
\begin{tabular}{c|c c c}
\hline
\hline
& & Satellite & IGM \\
& Merger & accretion & accretion \\
\hline
\HI\ & $\surd$ & $\times$ & $\surd$ \\
stellar populations & $\surd$ & $\times$ & $\times$ \\
shells & $\surd$ & $\surd$ & $\times$ \\
\hline
\end{tabular}
\end{table}