How is a bird respiratory system advantageous for them?

In contrast to their dinosaur ancestors, they lack true teeth and have replaced them with specialized beaks and bills. The respiratory system of birds facilitates efficient exchange of carbon dioxide and oxygen by using air sacs to maintain a continuous unidirectional airflow through the lungs.

Explanation:

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