Question

it lies __________ two main pieces​

Answer 1

It lies in two main pieces​ . In is the correct preposition.

Explanation:

Prepositions are basically followed by an object, which can be a noun, a noun phrase or a pronoun.

A preposition is a  very small and a very common word that shows direction  location or time or that introduces an object.

The most common prepositions are at, by, for, on, to, from, in, of and with.

For example:

Incomplete sentence:

It lies __________ two main pieces​

Complete sentence:

It lies in two main pieces​