Which environmental shift threatened pre-Columbian chinampa maize cultivation in the Valley of Mexico?

💡 Explanation

When lake levels rose significantly due to heavier rainfall, the chinampas experienced increased soil salinity because capillary action drew salts up from the lakebed, inhibiting maize growth. Therefore increased salinity resulted rather than ash, aquifer depletion, or acidity which involve alternative environmental causes.

• Which mechanical effect primarily enabled early steam engines to perform work in Newcomen's atmospheric engine?
• Which systematic hazard arose in 18th-century long-distance seafaring when using precise chronometers for longitude determination?
• Which optical consequence arises when grinding medieval glass lens with uneven pressure distribution?
• Which risk increases when a wooden sailing ship's hull remains consistently damp for extended periods?
• Which problem arose when medieval navigators used brass astrolabes to measure star altitude at sea during ship's roll?
• Which mechanical consequence was observed in early atmospheric steam engines due to repeated heating/cooling cycles?