40) which one of the following statements is believed to be true of comets? a) they have highly elliptical orbits around the sun. b) they are composed mostly of dense rock particles. c) they may gain slightly in mass with each orbit around the sun. d) their bright, glowing appearance in the night sky is due to frictional heating atmosphere. diff: 1

The correct statement for comet is - ( a ) They have highly elliptical orbits around the sun

Explanation:

The comet is made up by the composition of dust , water , ice , rock and frozen gases like , the carbon dioxide , methane , ammonia and carbon monoxide .

Comet shows a process called outgassing , i.e. , the comet passes close to the sun , then they start to release gases , which is visible in the form of a comet's tail .

The comet and its tail glows by the sun and becomes visible when the comet passes through the solar system , because the dust partials reflects sunlight directly and the gas glows due to ionization process.

The orbital of comet is usually highly eccentric elliptical path .

true. earthquakes are felt whenever there is a slip around a fault in the rocks below the earth. this reorientation of faults create sesmic waves and is known as earthquake, the severity of which is measured in richter scale. these are more prominent in hilly regions as the rocks usually form faults to balance the pressures on it.