'Nepal is common garden of many castes cultures and civilizations.' elaborate the statement.

The statement means that the small nation is home to many diverse cultures, civilizations, and tribes who all call it home and grow up, co-existing amongst themselves in harmony.

Explanation:

The statement that "Nepal is a common garden of many castes, cultures, and civilizations" means that the country is like a garden that houses a variety of tribes and cultures without any specific tribe or caste being allowed to reside alone. The statement is a metaphor, comparing Nepal with a garden that is made up of mixed varieties of tribes and cultures.

Though small the country may be, it is home to many tribes, many different cultures living peacefully, co-existing, and growing up together. It is a peaceful ground for the numerous cultures to grow up and develop, at the same time co-existing amongst themselves. Without a single tribe, a single civilization, or a single culture dominating or living in it, the complex yet mixed nature is what makes this small country a great example of secularity.  

aa

explanation:

literally the answer is aa. not kidding. aa is a group.

i r r e l e v a n t