Subterranean Geological Formations: PTE Highlight Incorrect Words practice questions

Click each word that differs from what the speaker says. Click again to unselect.

Mineral straws represent the final stage of stalactite development beneath cavern ceilings. Rainwater absorbs carbon dioxide while moving through soil, becoming slightly acidic before dissolving limestone rock. As this liquid drips into the chamber, it absorbs gas and leaves behind a microscopic ring of calcite. Over centuries, these delicate hollow tubes grow downwards, maintaining an exceptionally uniform width until mineral deposits widen their central channel.

Click each word that differs from what the speaker says. Click again to unselect.

Cave pearls develop within deep pools located on limestone floors where water drips steadily from above. Each structure begins around a tiny grain of sand or shell fragment that serves as a central nucleus. The constant agitation caused by falling water helps the sphere from sticking to the bedrock beneath. Thin layers of calcium carbonate coat the object continuously, producing a rough and rounded spherical shape over decades.

Click each word that differs from what the speaker says. Click again to unselect.

Unlike typical stalactites that depend entirely on gravity, helictites grow in unpredictable directions and form intricate curved shapes. Capillary forces draw mineral solutions through large internal channels at such a slow rate that droplets evaporate before falling. Hydrostatic pressure forces the liquid through the passage, allowing crystals to form sideways or even upwards. This simple growth process demonstrates how capillary mechanics can completely override gravitational pull in subterranean spaces.