An estuary can support abundant life for all of the following reasons except that an estuary a . is a nutrient trap b. receives plenty of sunlight c. maintains a constant salinity level d. has abundant plankton and rooted plants

C. Maintains a constant salinity level.

Estuary is a natural water body that forms when a fresh water source like river meets with the saline water source like ocean. It is a transition zone between freshwater river and salt water ocean. The water in the estuary is brackish which means it is moderately saline. But the extend of salinity often varies, depending upon the supply of water from freshwater from river source and salt water from oceanic source. The estuaries does not maintain a constant salinity level. The organisms living in the estuary water ecosystem are adapted for moderate salinity. But with the increase in the salinity level the organisms are not able to survive and reproduce.The increase in amount of salt in water also depletes the oxygen level in water. Therefore, organisms may either migrate to other locations or die.

the unequal cytoplasmic division that  results  in  one egg  and three polar bodies ensures that a fertilized  egg has  ample nutrients  forits journey  to  the uterus.

c: warm water flows from the western tropical pacific toward south america. that should be the right answer! hope it .