Question

what does the prefix hydro- mean in the word hydroplane? we rode across the swamp aboard a hydroplane in search of alligators. gas water energy air

Explanation:

The context states the hydroplane was used to travel across a swamp, which is a water-filled area. The prefix hydro- has a well-established meaning tied to water in English vocabulary, and this aligns with the scenario of a vehicle operating on a swamp.

Answer:

water