Formula One's plan to introduce an alternative engine from 2017 ultimately comes down to a question of who runs the sport, says Red Bull's Christian Horner.
Drivers will wear black armbands as a tribute to the victims of the Paris attacks when they are presented to F1 fans before Sunday's Brazilian Grand Prix.
McLaren drivers Fernando Alonso and Jenson Button stepped on the podium for the first time this season, but only in jest after another qualifying disaster.