The major group of organisms that fix nitrogen into ammonia and then oxidize it to nitrate are ________.
A. protozoa
B. bacteria
C. fungi
D. algae
Answer: B
You might also like to view...
You are conducting a long term study of ecosystem functioning in a freshwater lake. You and your field assistants gather data for many biotic and abiotic factors, including species diversity, water and benthic quality, and turbidity. Over the ten years of your study, you find that the abundance of water lilies is correlated with several other factors. When water toxicity and turbidity are high and water pH is abnormally low, water lilies quickly become scarce, followed by periods where fish, amphibians, and water birds are also scarce or absent. In years water nutrient levels are very high, water lilies quickly become abundant, followed by years where wading birds are scarce. From these data, you conclude that water lilies are __________.
A. an umbrella species. B. a keystone species. C. an endemic species. D. a flagship species. E. an indicator species.
Most reefs grow at depths of ________ meters or less
a. 15 b. 30 c. 60 d. 25
All releasing hormones produced by neurosecretory cells of the hypothalamus are
A) ions. B) peptides. C) steroids. D) modified amino acids. E) modified fatty acids.
What is the process by which a temperate bacteriophage infects a bacterial cell and subsequently integrates its chromosome into the bacterial chromosome?
A) transformation B) lysis C) transduction D) lysogeny E) temperate