Until Berta and Ernst Scharrer established the concept of neurosecretion in 1928, scientists believed that either cells secreted hormones, which made them endocrine cells and thus part of the endocrine system, or conducted electrical impluses, in which case they were nerve cells and thus part pf the nervous system.
A)either cells secreted hormones, which made them
B)either cells secreted hormones, making them
C)either cells secreted hormones and were
D)cells either secreted hormones, in which case they were
E)cells either secreted hormones, which mafe them
KEY: D
這一題用平衡法可以做出答案D
可是其實不懂題目在說什麼,可請哪為大大幫忙明示一下嗎?