In areas with heavy automobile traffic, however, the seed germinates in the absence of fire, with automobile exhaust supplying the required nitrogen dioxide.
然而，在汽车交通繁忙的地区，种子在没有火灾的情况下借助汽车尾气提供所需的二氧化氮发芽。
2
Massive stars end their lives with supernova explosions that spray the heavy elements into space, where they are incorporated into the next generation of stars and help seed the formation of planets.