Answer:
Water
Explanation:
The most likely means is water by which the zoospores spread from one living amphibian to another because amphibians lives in water and these zoospores can move in water and reach another amphibian causing infection to them. Amphibians are the organisms which lives both land and water. They requires water for reproduction so they lives at wet places. Zoospores have a unique structure which able them to swim in the water. So water is a great source of dispersal of zoospores from amphibian to amphibian.