When certain bodies of water develop regions known as "dead zones" it often means that:
A. Oxygen has been depleted.
B. Carbon dioxide is not available.
C. Nitrogen has become limited.
D. Phosphorus has killed animals.
E. Plant life no longer can survive.
A. Oxygen has been depleted.
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What is the primary disadvantage of being an osmoregulator?
A. Extra energy has to be used to pump ions into or out of the body. B. Extra energy has to be used to pump water into or out of the body. C. The central nervous system is deprived of critical information about the environment by keeping relatively constant internal conditions. D. Physiological systems do not typically perform well under relatively constant conditions.
Maintaining the volume and composition of body fluids is the direct responsibility of which system?
a. integumentary b. immune c. digestive d. urinary e. circulatory
The relationship between ants and acacias represents a defensive mutualism
Indicate whether the statement is true or false
Nitrogen gas in the atmosphere is converted to forms of nitrogen usable by vegetation via:
A) assimilation. B) fixation. C) denitrification. D) nitrification. E) decomposition.