Every system in this universe tries to reduce its energy. The shape of bubble is always round because the area is minimum in case of sphere for a given volume, which in turn reduces surface energy.
its not perfectly round .It is because of continuous bombardment in plasma due to fusion of hydrogen and release of their energy.
Nobody's head is perfectly round. It is a free-form shape. Everybody's is a different shape.
Is a circle.
Overal the shape of the planet Mars is round. However, there is some indentations in the planet that make it a little distorted and not perfectly round.
A cone, a section of a sphere.
It is a sphere
Bubbles are "generally" round due to the air pressure acting equally on them from all points around the outside of the bubble. A bubble is round as it is the most energy efficient configuration. The spherical shape also maximizes the ratio of the volume to the surface area.
a sphere
A ring will change shape after a while to adjust to the shape of your finger- don't worry about correcting it! have you ever looked at your finger? It isn't perfectly round! When a ring changes shape it will undoubtedly get more comfortable!
Rocks are eroded by waves and wind to form a perfectly round, smooth shape. It may take a very long time.
This is because the material the ballon is made of is shaped differently. The ballon will stretch and try to achieve a perfect round shape, but can not due to limitations in the way the ballon is made. One can however buy balloons that are almost perfectly round when inflated.
A sphere is the shape that has the largest volume and smallest surface area. the surface tension pulls the surface of the bubble in but the volume of air inside the bubble remains constant so the bubble wants to become a sphere.