— It's dangerous to swim here. Look at the sign.
— Oh, I notice it. Thanks for telling me.
细胞在生长过程中,当细胞体积逐渐变大时,表面积与体积之比( )
北极的极地狐耳朵小,沙漠的大耳狐耳朵大。造成这一差异的主要非生物因素是( )