Questions

Helioseismology is the study of the solar interior using observations of waves on the Sun's surface. It has done much to improve our understanding of the interior of the Sun, testing the physical inputs used to model stellar interiors and providing a detailed map of the Sun's structure and internal rotation.

An Element is a pure substance of one type of atom. In chemistry, any material such as carbon, hydrogen, iron, or oxygen that cannot be broken down into more fundamental substances is nothing but an element.

Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations.

The ball with which Table Tennis is played is called Ping Pong Ball.

According to the International rules, the diameter of the ping pong ball must be not less than 39.5 millimeters and not greater than 40.5  millimeters having a mass of 2.7 grams.