Ordinary rubber is an isulator. But the special rubber tyres of aircrafts are made slightly conducting. Why is this necessary?

Why conducting wires are made of copper?

Why are tyres made circular?

Why does a rubber can be compressed ?

Why should gases be insulators at ordinary pressure and start conducting at very low pressure?

Carry out the following osmosis experiment: Take four peeled potato halves and scoos each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water.(a) Now, Keep cup A empty.(b)Put one teaspoon sugar in cup B.(c)Put one teaspoon salt in cup c.(d)put one teaspoon sugar in the boiled potato cup D.Keep these for two hours then observe the four potato cups and answer the following: Why is potatoA necessary for this experiment?