单项选择题

From paragraph 1, we know that some 40 genes involving in cancer are（）

A．harmful to the human body
B．necessary to the human body
C．the elements that form cancer
D．useless to the human body

<上一题目录下一题>

热门试题

单项选择题

Where are most likely to be affected by caner-inducing agents according to the passage （）

A．The lung.
B．The colon.
C．The chromosomes.
D．The breast.

单项选择题

Under what conditions will the formation of cancer begin （）

A．When a chromosome breaks apart near an oncogene and its control functions fail.
B．When people drink too much and are easy to get tired.
C．When people smoke too much and are difficult to get to sleep.
D．When people eat too much petroleum-based products.