An axodine is a unicellular heterokont alga of the class Actinochrysophyceae.

Water molds are typically oomycetes. Oomycetes are in teh calde Stramenopila. They are separated from Fungi (including bread molds) by the their use of the DAP pathway for lysine synthesis, the presence of cellulose in their cell walls, their tubular cisternae in the mitochondria, heterokont flagella on their zoospores, and lack of a Spitzenkorper in their hyphae.

Fungi use the AAA pathway for lysine synthesis, have chitin in their cell walls, have plate-like cisternae in the mitochondria, a single whiplash flagellum, and use a Spitzenkorper to elongate their hyphae.

No, fungi are separated from them based on their plate-like cristae in the mitochondria, the possession of a single, posterior, whiplash flagellum (in some forms), synthesis of lysine by the AAA pathway, the use of glycogen as a storage compound, and the presence of the Spitzenkorper in actively growing hyphae.

Water molds (assuming you are referring to the oomycetes) have heterokont flagella--one whiplash and one tinsel--tubular cristae in the mitochondria, and the DAA pathway for lysine synthesis.

Slime molds engulf their food, which fungi do not. They also have 1-4 anteriorly directed flagella.

This is one of the most common types of phytoplankton in the oceans. They are eukaryotic algae which can either be unicellular or exist in filamentous or ribbon-shaped colonies. Since they are food producers towards the lower end of the food chain in the oceans, their behavior can often reflect changes in their environments.