Questions 18 to 20 are based on the following passage. At the end of the passage, you will be given 15 seconds to answer the questions.
Which of the following is CORRECT

A．Cells can remain alive outside limits of temperature.
B．Enzyme systems of mammals are efficient only within a narrow range around 37~
C． If the temperature is 38~C, the integrated actions of bodily systems will be damaged.
D．Other animals have a narrower tolerance for temperature changes than mammals and birds.