Answer:
The peroxide initiates the free radical reaction
Step-by-step explanation:
The addition of HBr to alkene in the presence of peroxides occurs via a free radical mechanism.
The organic peroxide acts as the initiator of the free radical reaction. The organic free radical interacts with HBr to produce a bromine free radical which now interacts with the alkene and the propagation steps continue until it is terminated by the coupling of two free radicals.
The peroxide effect leads to anti-Markovnikov addition.