Question

streptococcus pneumoniae is a kind of bacterium that
a. causes infections in humans
b. aids in the digestion of food
c. causes several types of cancer
d. supports the human immune system

Explanation:

肺炎链球菌（Streptococcus pneumoniae）是一种常见的致病菌，可引起人类多种感染性疾病，如肺炎、脑膜炎、中耳炎等。它并不具备帮助食物消化、引发多种癌症或支持人体免疫系统的功能。

Answer:

A. causes infections in humans