At night, schools of prey and predators are almost always spectacularly illuminated by the bioluminescence produced by the microscopic and larger plankton. The reason for the ubiquitous production of light by the microorganisms of the sea remains obscure and suggested explanations are controversial. It has been suggested that light is a kind of inadvertent by-product of life in transparent organisms. It has also been hypothesized that the emission of light on disturbance is advantageous to the plankton in malting the predators of the plankton conspicuous to their predators Unquestionably, it does act this way. Indeed, some fisheries base the detection of their prey on the bioluminescence that the fish excite. It is difficult, however, to defend the thesis that this effect was the direct factor in the original development of bioluminescence since the effect was of no advantage to the individual microorganism that first developed it. Perhaps the luminescence of a microorganism also discourages attack by light-avoiding predators and is of initial survival benefit to the individual. As it then becomes general in the population, the effect of revealing plankton predators to their predators would also become important.

The primary topic of the passage is which of the following?

A) The origin of bioluminescence in plankton predators
B) The disadvantages of bioluminescence in microorganisms.
C) The varieties of marine bioluminescent life forms
D) Symbiotic relationships between predators and their prey
E) Hypotheses on the causes of bioluminescence in plankton



The author mentions the activities of fisheries in order to provide an example of

A) how ubiquitous the phenomenon of bioluminescence is coastally
B) how predators do make use of bioluminescence in locating their prey
C) how human intervention imperils bioluminescent microorganisms
D) how nocturnal fishing expeditions arc becoming more and more widespread
E) how limited bioluminescence is a source of light for human use



The passage provides an answer to which of the following questions?

A) What is the explanation for the phenomenon of bioluminescence in marine life?
B) Does the phenomenon of plankton bioluminescence have any practical applications?
C) Why do only certain specimens of marine life exhibit the phenomenon of bioluminescence?
D) How does underwater bioluminescence differ from atmospheric bioluminescence?
E) What are the steps that take place as an individual microorganism becomes bioluminescent?