PSAT Writing and Language Practice Test 45

Questions 34-44 refer to the following information.

Killer Cells

My mother brags that her children have 34 especially resilient immune systems. As an adolescent, I understood this only as a vague, obscure advantage 35 of sorts my sister and I, paragons of robustness—defied infectious organisms. I recall being sick only twice during my childhood; the two to three days of rest, cool baths, pungent medicines, and bland broths seemed destined to go on forever, and I couldn't fathom the somber lives of other students in my class who were ill several times each year. As I 36 aging, my apparent durability only increased; occasionally, I suffered from a runny nose or a sore throat, 37 considering nothing more.

I never felt a need to investigate my favorable strength further 38 because my father was diagnosed with Lupus. Lupus is a chronic autoimmune disorder in which the immune system—the source of my vigor—mistakenly attacks healthy cells causing muscle and joint pain and inflammation. In essence, his microscopic armor had gone rogue. Imagine that—the cells that freed me from routine sicknesses like the common cold to life-threatening diseases like cancer were murderous in my father, unable to differentiate allies from 39 helpful cells.

In a healthy immune system, white blood cells, or leukocytes, work closely with the circular system and lymphatic system to locate and destroy threatening pathogens. 40 Unlike other systems of the body the immune system, is relatively invisible with soldiers housed throughout the body in the spleen, lymph nodes, thymus, and bone marrow. These leukocytes produce antibodies to destroy disease-causing invaders called antigens. Some cells are responsible for sending messages, generating specific antibodies, destroying infected cells, or 41 remembering previous invaders so that the body is ready for them the next time. While the body fights, you often experience fever, fatigue, 42 having swelling, or runny nose—hence, my rare ailments. Immunity looks different for everyone: we are born with some immunity, acquire more as we grow, and obtain others through vaccination. Even then, each body defends differently and with varying degrees of efficiency.

A confused immune system, like that of my father, doesn't operate so. Instead, the leukocytes cannot determine friend from foe and attack healthy tissues in the same way they might attack virus and bacteria. Lupus can affect almost any organ in the body and varies in symptoms making it tough to diagnose and even more difficult to treat. My father experiences pain on a daily basis; his joints and muscles ache constantly, and he is often too tired to perform routine daily activities. His form of Lupus, Systemic Lupus Erythematosus, infects millions of people and 43 produces symptoms similar to Crohn's disease and Lyme disease. It is as if his troops simply turned against him. 44