[问答题] 什么是自然人？

肋膈沟常见于 ["正常儿童 ","佝偻病患儿 ","先天性异常 ","肺气肿 ","肺不张"] 什么是经验？ 下列哪种恶性肿瘤，常可转移到左锁骨上淋巴结 ["甲状腺癌 ","肺癌 ","乳腺癌 ","胃癌 ","鼻咽癌"] 胸腔积液病人，常采取的体位是 ["健侧卧位 ","患侧卧位 ","自动体位 ","端坐位 ","被动体位"] 会堂教育时期定义 什么是自然人？