Up till now, the moon is known as a (an) __________ place because nothing can live or grow there.
真核生物进行有性生殖时,通过减数分裂和随机受精使后代( )
杭州人有元宵节吃汤圆的习俗,当把生汤圆放进锅中时,由于浮力____重力,汤圆就会沉入锅底.