Can anybody help?? It's for a upcoming test and I need serious help ATM, I didn't study but I'll learn my lesson and do the work next time, I'd be grateful if somebody answered all of them!!

Why is it important always to use horizontal bars in unit fractions when performing unit conversions?

Students in an introductory physics lab are performing an experiment with a parallel-plate capacitor made of two circular aluminum plates, each 11 cm in diameter, separated by 1.0 cm. how much charge can be added to each of the plates before a spark jumps between the two plates? for such flat electrodes, assume that value of 3×106n/c of the field causes a spark.

Which form of cell division creates the sperm and egg, resulting in half of the chromosomes as the other cells?