Question

It seems likely that a number of astronomical phenomena, such as the formation of planetary nebulas, may be caused by the interaction where two stars orbit each other at close range.

(A) may be caused by the interaction where two stars orbit each other
(B) may be caused by the interaction between two stars that each orbit the other
(C) are because of the interaction between two stars that orbit each other
(D) are caused by the interaction of two stars where each is orbiting the other
(E) are caused by the interaction of two stars orbiting each other

Answer 1

Answer:(E) are caused by the interaction of two stars orbiting each other.

Explanation: Planetary Nebula were first observed by an Astronomer known as Williams Herschel at about the late 18th Century. It is believed to occur during the end of the life span of Giant Red Stars which are about 1-8 the mass of the Solar system.

Planetary Nebula is described as the expanding emission of ionised gases from the outer shell of this Giant Red Stars which are likely to be formed by interacting Stars orbiting each other.