Which of the following organism have siliceous skeletons?
Answer: C
Radiolaria and silicoflagellates have siliceous skeletons whereas foraminifera and coccolithophores produce calcareous skeletons.
Which of the following product is not obtained from dissimilation of organic matter under aerobic conditions?
Answer: C
Under aerobic conditions the principal products resulting from dissimilation of organic compounds are ammonium, carbon dioxide, sulphate, and phosphate.
In which of the following water bodies, fertility is high?
Answer: B
Although coastal and estuarine regions provide a less stable physical environment, their fertility exceeds that of the open sea because of the large amounts of nutrients available.
Which among the following oceans is the most richest in life?
Answer: A
The Antarctic Ocean is described as being richer in life than any other major oceanic area. The richness of nutrients in this region is attributable to the mixing of the waters of the Atlantic, Pacific, and Indian Oceans.
Which among the following factors are limiting the growth of phytoplankton organisms?
Answer: D
The factors generally limiting growth are radiant energy, nitrogen and phosphorus, and the trace elements. The nitrogen, phosphorus and trace elements are made available through the mineralization reactions of microorganisms.