Author's Purpose Practice Test

The glow of a firefly on a warm summer evening is a magical sight, but it is not magic—it is chemistry. This phenomenon, known as bioluminescence, occurs when a chemical called luciferin mixes with an enzyme called luciferase, oxygen, and a special energy-carrying molecule. This reaction produces light without generating much heat, which is why fireflies are sometimes called “cold lights.” The primary function of these flashes is communication. Each firefly species has its own unique flashing pattern, a sort of Morse code used to attract mates. A male will flash a specific sequence, and if a female of the same species is interested, she will flash back a particular response. This light is also a defense mechanism, as the firefly’s blood contains a chemical that tastes bitter to predators. The bright flash serves as a warning: “I taste bad, don’t eat me!”

The ancient art of origami transforms a flat sheet of paper into a three-dimensional sculpture through folding. The word itself comes from the Japanese words ori (folding) and kami (paper). While its exact origins are debated, origami became a popular art form in Japan during the Edo period (1603-1868). The core principle of traditional origami is that the sculpture should be created using only folds—no cutting, gluing, or marking the paper is allowed. This constraint is what makes origami both a challenge and a marvel. Artists must use a series of precise mountain folds (creases that point up) and valley folds (creases that point down) to create everything from simple boxes to intricate dragons. More than just a craft, origami is used by scientists and engineers to solve real-world problems, such as designing folded airbags for cars and collapsible telescopes for space missions.