all the living things _,couldn't live without air or water

选择A.
C的错误在于：“不应该加animals or plants”,因为what they are 中的what 就是they are 的表语,而animals or plants也是表语,没有双表语的机构.
这句话的意思是”不管是动物还是植物,所有生物不能再没有空气或水的情况下生存.“.
A.whether they are animals or plants 是whether 引导的插入语,起到补充说明的作用.�����no matter what the animals or plants ���ǶԵ�ô����,���ǿ��Ըijɡ�no matter what they are���������ָķ�����all the living things���޷����ӡ��﷨��˵��ͨ���ǿ������ɲ����no matter what they are��,�Ͳ�Ҫanimal or plants������֡�Ҫ�Ƿ�Ҫǿ����animal or plants�������ô�A,���ߡ�no matter what they are, animals or plants���������animal or plants�� �൱�ڲ���ɷ֡�