What is the first step of the calvin-benson cycle?
atp and nadph combine to make g3p.
g3p is used to make glucose and other
compounds.
atp and g3p combine to make rubp.
carbon dioxide and rubp combine to make pga.

In stage 1., the enzyme RuBisCO incorporates carbon dioxide into an organic molecule, 3-PGA.

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