Geography
Physical geography of Brazil
Know the relief (planalto, depressões, planícies), hydrographic basins (Amazônica, Tocantins-Araguaia, Paraná, São Francisco), and climate types (equatorial, tropical, semiárido, subtropical). Trap: confusing domínio morfoclimático (Ab'Sáber) with bioma; the cerrado is a biome and a morphoclimatic domain with distinct soil acidity.
Human and economic geography
Understand demographic transition, urbanization (metropolization, conurbação), agrarian structure (latifúndio, reforma agrária), energy matrix (hydro dominance, wind expansion), and transport corridors. Traps: stating that Brazil's energy matrix is mostly thermal, or confusing mesorregião with microrregião.
Geopolitics
Amazon (sovereignty, deforestation, monitoring), Prata basin, Antarctica (Treaty of 1959), maritime zones (12 nm territorial sea, 200 nm EEZ), and Brazil's claim to the Amazônia Azul.
Worked example
If an item asks which factor most explains Brazil's low rail share, the best answer is historical highway prioritization and continental distances, not lack of demand alone.
Rule of thumb
Always connect a physical feature to a human use (basin → energy/transport; climate → agriculture) to answer applied items.