Test de muestra
Part 3
For questions 17 - 24, read the text below. Use the word given in capitals next to each gap to form a word that fits in the gap.
Esto es una muestra. Cada test del libro tiene ocho huecos; aquí te dejamos cuatro para que veas el formato y el estilo de las claves. Los otros cuatro van ya resueltos dentro del texto.
Example: 0 UNDENIABLE
The mystery of bird migration
Bird migration is a (0) SPECTACULAR (SPECTACLE) annual event. Every autumn, billions of birds embark on (17) ____ (BELIEVE) long journeys across continents and oceans. Indeed, their (18) ____ (NAVIGATE) abilities have fascinated scientists for centuries, since many species travel thousands of miles with astonishing precision. These journeys, in fact, test the birds' physical (19) ____ (RESIST) to the absolute limit. Recent research suggests that birds rely on the Earth's magnetic field, following it (20) ____ (INSTINCT) rather than through learned behaviour. Young birds raised in isolation still orient correctly on their first migration, which rules out imitation as the sole explanation. Furthermore, some species are strictly migratory, following routes that have remained unchanged for millennia. However, human activity is now causing severe disturbance to these fragile pathways. Although scientists are working hard, climate change is making traditional breeding grounds steadily warmer. Despite the mounting risks, the ecological benefits of migration far outweigh the dangers, ensuring the survival of countless species. Light pollution along the coast is now recognised as a significant hazard, since artificial glow disorients birds that navigate partly by the stars.