1. What does destruction refer?

the earth's vegetated surface.
A) 20

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B) 50
C) 75
D) 20
E) 98
104
. Choose the correct determination for “chemical pollution” as a stress factor in 
ecosystem modelling.
A) They are are associated with interactions occurring among organisms, such as 
competition, herbivory, predation, parasitism, and disease. For example, individuals of the 
same or different species may compete for essential resources that are limited in supply. 
Herbivory, predation, parasitism, and disease are trophic interactions, in which one 
species exploits another. Exploitation can be anthropogenic, as when humans harvest wild 
animals or trees, or it can be natural, perhaps associated with defoliating insects or 
disease-causing pathogens
B) Stressor is caused by excessive exposure to ionizing energy. The radiation may be 
emitted by nuclear waste or explosions, or it can be diagnostic X-rays or solar ultraviolet 
energy
C) It occurs when people release organisms beyond their natural range. This might involve 
the introduction of alien species that invade and alter natural habitats, or it may be the 
release of pathogens into the environment through discharges of raw sewage
D) It occurs when one or more substances occur in a concentration high enough to elicit 
physiological responses in organisms, potentially causing toxicity and ecological change. 
Such types of stressors include pesticides, gases such as ozone and sulphur dioxide, and 
toxic elements such as arsenic and mercury. Pollution may also be caused by excessive 
nutrients, which can distort productivity and other ecological functions. Note that the mere 
presence of a potentially toxic agent does not necessarily cause pollution
E) It may occur at natural springs and submarine vents where geologically heated water is 
emitted. It is also associated with discharges of hot water from power plant