I need help ASAP

PLIS

Mouth: Closed. Operculum: Opened. Floor of buccal cavity: Raised

Explanation:

When fish breathe out, the mouth closes and muscles raise the floor of the buccal cavity and push in the walls of the operculum. The opercula opens and water is pushed out over the gills' surface.

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answer: - few nutrients

high pressure

low temperatures

explanation: 1. few nutrients:   open-ocean zone is located way far from the land, which is the main source of the essential nutrients.2. high pressure: pressure increases by 1 atmosphere for every 10 meters increase in depth.3. ample sunlight: a large fraction of the sunlight is reflected back to the atmosphere from the sea surface. 4. varying salinity: below the thermocline, the water is isolated from the atmosphere so the salinity remains stable over the year.5. low temperatures:   the temperature of open-ocean zone ranges from a low of -2°c to an average of 17°c