Unfortunately for coral reefs, however, a variety of human activities are causing worldwide degradation13 of shallow marine habitats by adding nutrients14 to the an increasing abundance of algae and filter-feeding animals. Declines in reef communities are consistent with observa- tions that nutrient input15 is increasing in direct proportion to growing human populations, thereby threatening reef com- munities sensitive to subtle changes in nutrient input to their waters.
1. The passage is primarily concerned with
describing the effects of human activities on algae in coral reefs
explaining how human activities are posing a threat to coral reef communities
discussing the process by which coral reefs deteriorate16 in nutrient-poor waters
explaining how coral reefs produce food for themselves
describing the abundance of algae and filter-feeding animals in coral reef areas
2. The passage suggests which of the following about coral reef communities?
Coral reef communities may actually be more likely to thrive in waters that are relatively17 low in nutrients.
The nutrients on which coral reef communities thrive are only found in shallow waters.
Human population growth has led to changing ocean temperatures, which threatens coral reef communities.
The growth of coral reef communities tends to destabilize underwater herbivore populations.
Coral reef communities are more complex and perse than most ecosplayystems18 located on dry land.
3. The author refers to filter-feeding animals in order to
provide an example of a characteristic sign of reef deterioration19
explain how reef communities acquire sustenance20 for survival
identify a factor that helps herbivore populations thrive
indicate a cause of decreasing nutrient input in waters that reefs inhabit
identify members of coral reef communities that rely on coral reefs for nutrients
4. According to the passage, which of the following is a factor that is threatening the survival of coral reef communities?
The waters they inhabit contain few nutrient resources.
A decline in nutrient input is disrupting their symbiotic relationship with zooxanthellae
The degraded waters of their marine habitats have reduced their ability to carry out photosynthesis
They are too biologically complex to survive in habitats with minimal21 nutrient input.
Waste by-products result in an increase in nutrient input to reef communities.
5. It can be inferred from the passage that the author describes coral reef communities as paradoxical most likely for which of the following reasons?
They are thriving even though human activities have depleted22 the nutrients in their environment.
They are able to survive in spite of an over- abundance of algae inhabiting their waters.
They are able to survive in an environment with limited food resources.
Their metabolic wastes contribute to the degra- dation of the waters that they inhabit.
They are declining even when the water sur- rounding them remains clear
