In 2018, F1 teams are allowed only 3 units of the Internal Combustion Engine, MGU-K and MGU-H, and 2 units of Energy Store, Turbocharger and Control Electronics. Gearboxes must also be used for 6 consecutive race weekends (FP3 to Race) before teams could replace them without penalty.
Question is, how does the FIA keep track of these components and make sure that the teams are not changing them between each race weekend?