Sometimes, a crackling sound is heard while taking off a sweater during winters. Explain.

The heart sound murmur is heard during

A car sometimes overturns while taking a turn. When it overturns, it is

Sometimes when a vehicle is driven at a particular speed, a rattling sound is heard. Explain briefly, why this happens and give the name of the phenomenon taking place.

During winter, sometimes we see a white trail at the back of a flying aeroplane in a clear sky. Explain why.

Some varieties of wheat are known as spring wheat while others are called winter wheat. Former variety is sown and planted in spring and is harvested by the end of the same season. Hower winter varietis if planted in spring fail to flower or produce mature grains within a span of a slowering season . Explain, why?