In marine habitats, a number of small creatures are involved in a "cleaning symbiosis." At least six species of small shrimp, frequently brightly colored, crawl over fish, picking off parasites and cleaning injured areas. This is not an accidental occurrence, because fish are observed to congregate around these shrimp and stay motionless while being inspected. Several species of small fish (wrasses) are also cleaners, nearly all of them having appropriate adaptations such as long snouts, tweezers-like teeth, and bright coloration. Conspicuous coloration probably communicates that these animals are not prey.
several species of fish are unlikely to be eaten by big fish because ________
a. they clean the parasites found in marine habitats
b. they stay motionless while being inspected
c. they are very brightly coloured cleaner fish
d. they have appropriate adaptation as cleaners
e. they usually gather around other creatures
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