1. Mercedes had a lot of issues regarding tyre degradation since the start of the season, although, after some illegal testing (already penalized) they've improved a lot. so they can keep up with red bull.
2. There's 3 stages in qualifying stages, in the first one(20min), the 6 slowest drivers get eliminated. In the second one (15min) the slowest 6 get eliminated again. In the third one the 10 fastest drivers battle for their respective grid positions. Mark webber got through 2 qualifying stages, but did not set a time in Q3, so he got 10th place.
3. Besides the setup (suspension, engine mapping, gear ratios), usually, the top 5 cares aren't very different from each other, mostly beacuse of the harsh regulations, In F1 however, a milisecond can make all the difference. Team engineers work around the clock to extract the maximum amount of performance from the car. Red bull pours a lot of money into engineers and designers in order to have the best car on the grid. According to Frank williams 25% of the speed comes from the tyres and tyre management, 25% comes from the car itself, and the other 50% comes from the driver.
4. You're allowed to defend yourself once from another driver, for example, if a driver is trying to pass another driver in straight and tries to get through the right side of the circuit, the defending driver, can block from the right, but then if the attacking driver tries again from the left. the defending driver can't outright block him again.
5. there's 1 DRS detection spot in each circuit, if a car is 1 second or less away from the other car when going through the detection zone, he's allowed to use DRS.
6. Harder tyres, are often more desired because they are more predictable and last longer even though they are slower.
8. If the race marshalls think a driver got an unfair advantage by cutting a corner he will be penalized.
9. It means that they should disable a sensor (on the engine, Ithink) in the car because it's not working properly.