[单项选择]

Immune Functions

The immune system is equal in complexity to the combined intricacies of the brain and nervous system. The success of the immune system in defending the body relies on a dynamic regulatory communication network consisting of millions and millions of cells. Organized into sets and subsets,these cells pass information back and forth like clouds of bees flying around a hive (蜂巢). The result is a sensitive system of checks and balances that produces an immune response that is prompt, appropriate effective, and self-limiting.
At the heart of the immune system is the ability to distinguish between self and no self. When immune defenders encounter cells or organisms carrying foreign or nonself molecules,the immune troops move quickly to eliminate the intruders(入侵者). Virtually every body cell carries distinctive molecules that identify it as self. The body’s immune defenses do not normally attack tissues
A. self-tolerance
B. balance
C. harmony
D. tolerance

[单项选择]

The immune system is equal in complexity to the combined intricacies of the brain and nervous system. The success of the immune system in defending the body relies on a dynamic regulatory communication network consisting of millions and millions of cells. Organized into sets and subsets,these cells pass information back and forth like clouds of bees flying around a hive (蜂巢). The result is a sensitive system of checks and balances that produces an immune response that is prompt, appropriate effective, and self-limiting.
At the heart of the immune system is the ability to distinguish between self and no self. When immune defenders encounter cells or organisms carrying foreign or nonself molecules,the immune troops move quickly to eliminate the intruders(入侵者). Virtually every body cell carries distinctive molecules that identify it as self. The body’s immune defenses do not normally attack tissues
A. The immune system’s memory.
B. Immune troops eliminating intruders.
C. Bees flying around a hive.
D. A sea of microbes.

[单项选择]The immune system is equal in complexity to the combined intricacies of the brain and nervous system. The success of the immune system in defending the body relies on a dynamic regulatory communications network consisting of millions and millions of cells. Organized into sets and subsets, these cells pass information back and forth like clouds of bees swarming around a hive. The result is a sensitive system of checks and balances that produces an immune response that is prompt, appropriate, effective and self-limiting. 　　At the heart of the immune system is the ability to distinguish between self and non-self. When immune defenders encounter cells or organisms carrying foreign or non-self molecules, the immune troops move quickly to eliminate the invaders. Virtually every body cell carries distinctive molecules that identify it as self. The body’’s immune defenses do not normally attack tissues that carry a self marker. Rather, immune cells and other body cells coexist peaceably in a
A. is no less complicated than the nervous system.
B. far exceeds the human brain in intricacy.
C. is surrounded by numerous sensitive cells.
D. results in an effective communications network.