How are insects preserved in an insect museum?

What are the main components found in the major botanical gardens of the world?

What is the process of treating herbarium sheets to prevent fungal and insect attacks called?

Assertion $A$: Many new and improved varieties of fruits,vegetables,and flowers can be obtained through research in botanical gardens.
Reason $R$: Processes like grafting,tissue culture,hybridization,cloning,and the development of germplasm banks are carried out in botanical gardens.
Which option is correct for Assertion $A$ and Reason $R$?

$A:$ Botanical gardens are an $ex-situ$ conservation strategy for plants.
$R:$ The National Botanical Garden is situated at Howrah.

Ecological,economic,and ethnobotanical information is obtained from .........