What is the square root of negative one?

answer is a: las

explanation:

the reason for this answer is becouse it's a plural frase which talks more then one thing

ancient india is often called the harappan civilization because one of the ancient cities was called harappa. harappa was just one of 1500 cities in the indus river valley. another well-known city is called mohenjo-daro. historians estimate ancient india to be the biggest of all four early civilizations.