The reason ______she didn’t come to school was_____

she had to look after her sick mother.

A．because ; why

B．that ; because

C．why ; that

D．which ;that

与真菌菌丝伸长生长有密切关系的细胞器是（）。

A、液泡

B、几丁质酶体

C、膜边体

D、氢化酶体