In the Gulf of Mexico, there is a large area off the coast of Louisiana that cannot support most marine life. In this area, fresh water from the Mississippi River carries excess phosphorus and nitrogen from lawn care and agriculture into the Gulf of Mexico. Algae in the water use these nutrients to grow rapidly, creating algal blooms in the water. When the algae die, they sink to the bottom of the Gulf, where bacteria use much of the oxygen in the water to decompose the algae. Dissolved Oxygen Levels in Gulf of Mexico Dead Zone
map showing dissolved oxygen levels in water, with areas ranging from 0 mg/L to about 6mg/L
Image courtesy of NOAA

Marine organisms trying to live in the water may not get enough oxygen to survive. Based on this description, which of the following is true?
A.
The supply of any nonliving factor supports or limits growth of all organisms in an ecosystem in the same way.
B.
The number of organisms of each type in an ecosystem depends on living factors but not on nonliving factors.
C.
Living factors, such as the number of producers present, play the largest role in the survival of organisms in an ecosystem.
D.
Nonliving factors, such as the amount of nutrients available, significantly affect the survival of organisms in their environment.
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