Which living animal have the largest carnassial teeth? Compare the characteristics of mammals and birds, noting the similarities and differences between the groups. Why don't we consider mammals and birds closely related with a common ancestor, since they are both "warm-blooded"?
aWhat should you do if you want to have a healthy body 什么应该您做,如果您想要有一个健康身体[translate] a鲸家族一般分为两大类,一类是须鲸,十分温柔,而且没有牙齿;一类是齿鲸,有十分锋利的牙齿,只吃大鱼和海兽,从不吃那些小鱼小虾。 哺乳动物不同之处除了体积大之外就是鼻孔了,鼻孔是长在头顶上的,...