As they near the sun, the sun's heat melts the comet's ices and releases dust particles which are most evident as the comet's tail.
(the sun's heat; melts; the comet's ices; T:As they near the sun) (the sun's heat; releases; dust particles which are most evident as the comet's tail; T:As they near the sun) (dust particles; are; most evident as the comet's tail)
the sun's heat the sun's heat dust particles
melts releases are
the comet's ices T:As they near the sun
dust particles which are most evident as the comet's tail T:As they near the sun
most evident as the comet's tail