题目

There was a young girl who was raised in circumstances where three meals day was a luxury. Her family was so poor that she couldn’t afford footwear or books. She would wear overly long dresses to school so her class mates wouldn't notice her bare feet. Her father had old fashioned ideas about how sons vs. daughters should be raised. However, a sympathetic colleague of his at work would sneak his daughter paper that was used only on one side. The girl would then sew them into a notebook and use those at school. Since she couldn’t afford textbooks either, she would borrow them from h下列关于反射和反射弧的叙述正确的是（  ）A．反射弧是神经系统结构和功能的基本单位 B．反射活动必须通过反射弧来完成C．只要有完整的反射弧，必然出现反射活动 D．反射和反射弧在性质上是完全相同的