A:比原来的冷水温度低
B:比原来的热水温度高
C:接近两杯水的温度的平均数
如图,如图,共有____条射线.
.
Nowadays, more and more students choose to take a gap year. That is, they take a year ____ between the ending of high school and the beginning of university.
下列关于育种的相关叙述,正确的是( )
机体维持内环境稳态的主要调节机制是( )