Which of the following is a storehouse of collected plant specimens?

Which one of the following taxonomical aids is used for the identification of plants and animals based on the presence or absence of contrasting characters?

The famous herbarium of India,which is located in Kolkata,is known as:

Where is the National Botanical Research Institute $(NBRI)$ located?

How are plants displayed in a botanical garden?

Couplet represents the choice made between two opposite options which results in