How are plants displayed in a botanical garden?

Write a short note on Botanical Gardens.

Which of the following taxonomical aids is being described by the given statements $(i-iv)$?
$(i)$. They are generally established in educational institutes.
$(ii)$. They have collections of preserved plant and animal specimens for study and reference.
$(iii)$. Insects are preserved in boxes after collecting,killing,and pinning.
$(iv)$. They often have collections of skeletons of animals too.

Where is the Indian Botanical Garden located?

Statement $S$: The Museum of Natural History is located in England.
Reason $R$: The Herbarium of Forest Research is located in Kolkata.
$(a)$ Both $S$ and $R$ are true,$R$ is the correct explanation of $S$.
$(b)$ Both $S$ and $R$ are true,but $R$ is not the correct explanation of $S$.
$(c)$ $S$ is true and $R$ is false.
$(d)$ Both $S$ and $R$ are false.

Why are botanical gardens necessary?