Reading Comprehension · Science
PrepTest 112 · Section 2 · Passage 3
Questions 15–20
Before you start
Open PrepTest 112, Section 2 in your official copy from LSAC and read the passage for Questions 15–20, using the structure guide below. The passage is not reprinted here.
Structure guide
- P1: notes what earlier work focused on, announces a newer, wider finding, and defines the balancing system the rest of the passage explains
- P2: explains how the system works step by step, with two opposite cases, a quiet fix and a visible behavior working together, and closes with which of the two kicks in first
Step 2 · The kid passage
The Card That Counts Crayons
For years, kids who wrote about Ms. Rivera's colored cards talked about one job only: the green card starts recess, and that same green card also sends everybody to the line. Neat and tidy, one card, two jobs. Lulu's clipboard now shows something new. Other cards also steer what kids do. The yellow card and the blue card, which help keep the crayon bin balanced, also decide whether kids go asking for crayons. A balanced bin means about thirty crayons, no matter how wild art day gets. The class keeps it steady mostly by changing how many crayons come in and go out, and it starts fixing things while the drift is still tiny.
Small wobbles bother nobody, because the spare cup on the shelf soaks them up. But sometimes the count swings past a couple of crayons. Then two kinds of fixes team up, one quiet and one you can see. When the bin is overstuffed, say after a big donation, Ms. Rivera keeps the yellow card down. Without it, the helper stops saving crayons, and the extras go back to the art room. Kids also stop asking families for more, so the bin does not get even fuller. When the bin runs low, the yellow card goes up. The helper keeps every crayon, and kids start asking families for donations. The asking starts a bit later than the card, though: only once the helper has saved all she possibly can.
Step 4 · The courtroom tale
The Case of the Steady Shelf
Mr. Whitfield snapped his suspenders. "Your Honor, my client's cereal shop is accused of chaos. Watch." The shop owner took the stand. "Earlier write-ups of our bells only covered the morning bell, which unlocks the doors and also calls the staff. But our shelf bell does two jobs too." She explained: when the cereal shelf overflows, she keeps the shelf bell silent, the stockroom stops sending boxes, and the 'Buy Two' sign comes down, so shoppers do not pile up more orders. When the shelf runs thin, the bell rings, the stockroom holds every box for the shelf, and later the sign goes up. "The sign always comes last," she said, "after the stockroom has done all it can." The judge nodded. "Not chaos. Balance."