GRE Reading Comprehension: OG/PP2-GRE阅读OG/PP2 - WJ4GOJFR9SA85TMOP

According to the passage, which of the following factors help account for the elliptical shape of the orbits of extrasolar planets? A. The planets' formation in close proximity to other planets B. The gravitational influence of planets whose original orbits have been disturbed C. The gravitational influence of comets