Which solution is used to preserve specimens in a jar?

Which areas are selected for field studies?

The works of which scientists have served as a guide for plant identification,arrangement in herbaria,and the preparation of regional floras?

Where is the Lloyd Botanical Garden located?

The famous botanical garden '$Kew$' is located in

Assertion $A$: Herbaria provide keys for preparing modern taxonomic systems.
Reason $R$: Herbaria provide facilities for taxonomic research.
Which option is correct for Assertion $A$ and Reason $R$?