Study the following and choose the correct statements.
\[
\begin{aligned}
\text{I.} \;& \text{Biodiversity is greater in tropics} \\
\text{II.} \;& \text{Digitalin is an anti-cancer drug obtained from the plant } \textit{Vinca rosea} \\
\text{III.} \;& \text{Invasion of alien species is a threat to the local species} \\
\text{IV.} \;& \text{Sacred groves are a type of ex-situ conservation}
\end{aligned}
\]
(only = only)
