What would the product look like if roor weren't used?

The least substituted product (anti-Markovnikov)

Explanation:

The ROOR is used in the addition reaction of HBr to an organic substance (an alkene for example).

In normal conditions (with no ROOR) the adition of the halogen will be performed in the most substituted C (following the rule of Markovnikov that says that the stability increases with the more substituted is the C).

But in presence of ROOR, the reaction takes other mechanism (free radicals), and the product in this case is the one with the Br added in the least substituted C.

a) the particles of the chair are strongly held together.