Practice question

“Temperature and precipitation” for what is the primary climatic factor that determines biome distribution. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Plant growth form integrates water balance, fire, frost, nutrient availability, and growing-season length. Animals respond to the same filters through migration, dormancy, thermoregulation, and dietary specialization. The remaining alternatives—“Wind direction”, “Ocean salinity”, “Soil depth”—refer to different states, processes, or scales and therefore do not express the same causal relationship. 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. Linking the wording to measurable consequences for fitness, abundance, or flux gives the conclusion its scientific meaning and prevents a purely mnemonic interpretation. Field observations could test this account by measuring the proposed driver and the demographic or ecosystem response while controlling plausible confounding factors.