中纬度是指( )
A:0°~30°
B:23.5°~66.5°
C:30°~60°
D:60°~90°
2的算术平方根()
豌豆种子的黄色对绿色为显性,圆粒对皱粒为显性.现有黄色圆粒和绿色皱粒两个纯种品系,用它们作亲本进行杂交,再使F1自交,得F2,为获得稳定遗传的绿色圆粒豌豆,对F2还应( )
— What a touching love story! The main character Song Joongki in the Korean drama Descendants of the sun(太阳的后裔)acts very well.
— Really? When _______ it?