1. define fitness as it used to describe adaptation(11.3).

ysosomes are membrane-bound vesicles that contain digestive enzymes, such as glycosidases, proteases and sulfatases. lysosomal enzymes are synthesized in the endoplasmic reticulum (er), are transported to the golgi apparatus, and are tagged for lysosomes by the addition of mannose-6-phosphate label.

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