Practice question

“30–50 cm” for what is the rainfall range in chaparral biomes. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. A biome label describes a broad climatic and structural pattern rather than a single taxonomic assemblage. Similar climates can produce convergent vegetation on different continents even when the species themselves are unrelated. The remaining alternatives—“10–20 cm”, “60–80 cm”, “100–200 cm”—refer to different states, processes, or scales and therefore do not express the same causal relationship. Terrestrial biomes are distinguished primarily by long-term temperature and precipitation regimes, their seasonality, and the vegetation physiognomy those conditions support. Latitude is informative only because it often covaries with climate. Field observations could test this account by measuring the proposed driver and the demographic or ecosystem response while controlling plausible confounding factors. This distinction matters because similar surface patterns can arise through different mechanisms, whereas ecological prediction depends on identifying the mechanism that actually changes rates.