Direction: In the following passage there are blanks, each of which has been numbered. Find out the appropriate words.

After years of ______ (1) ______ over whether Pluto is a planet, in 2006 the International Astronomical Union (IAU) voted to remove Pluto’s planetary status. Now some researchers are ______ (2) ______ this decision, citing the manner in which scientific tradition has dealt with the taxonomy of planets. The IAU, in 2006, designated Pluto a ‘dwarf planet’ along with Ceres in the asteroid belt and Xena, an object in the Kuiper belt, which is an icy ring of frozen objects that circle the solar system beyond Neptune’s orbit. It was a bid to overcome sentiment and go by a scientific rationale. The meeting defined three conditions for a celestial object to be called a planet: one, it must orbit the Sun; two, it should be massive enough to acquire an approximately spherical shape; three, it has to ‘clear its orbit’, that is, be the object that ______ (3) ______ the maximum gravitational pull within its orbit. Owing to this third property, if an object ventures close to a planet’s orbit, it will either collide with it and be accreted, or be ejected out. However, Pluto is affected ______ (4) ______  Neptune’s gravity. It also shares its orbit with the frozen objects in the Kuiper belt. Based on this, the IAU ______ (5) ______ that Pluto did not ‘clear its orbit’. Dwarf planets, on the other hand, need only satisfy the first two conditions.