A:①②③④
B:①③②④
C:②④①③
D:①④②③
下列物质在氧气中燃烧有关现象的描述,正确的是( )
Lillian said memorizing the words of pop songs helped _________.
different, of, places, the, come, they, from, world(. )(连词成句)
原核生物、真核生物、病毒的遗传物质依次是( )
①DNA ②RNA ③DNA和RNA ④DNA或RNA.