两栖类原始生殖细胞的形成与卵子中称为（）的一种卵质决定子有关。
参考答案：生殖质
The old over 90 __ not only by their family but also by the government in many places.
A．is looked at
B．are taken good care of
C．are taken good care
D．is looking after
城镇用户用气设备包括：（）
A.灶具、热水器；
B.用户燃气管道；
C.燃气工业炉、燃气锅炉；
D.燃气空调机、民用燃气用具等；
