When the photosynthetic organisms evolved the ability to split water, they produced _____ as a waste material, which was poisonous to most of the cells then alive
a. hydrogen gas
b. hydrogen sulfide
c. water
d. carbon dioxide
e. oxygen
E; The earliest photosynthesizers used H2, H2S, and other sources of hydrogen atoms. Only when cells developed processes for splitting water did they begin to release O2 as a by-product.
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Glucose is converted into glycogen primarily in the ____
a. brain b. blood c. pancreas d. spleen e. liver
Which of the following most often leads to allopatric speciation?
A. Habitat isolation B. Mating time differences C. Gametic incompatibility D. Behavioral isolation
Which of the following mutations is considered a synonymous change?
A) ACC to AUG B) CUU to AUU C) CUU to CUA D) CUU to CUA E) UUU to UUA
Which of the following does not contribute to limits on population growth?
a. snakes feeding on mice in a cornfield b. bears having two cubs c. the amount of light for photosynthesis d. a disease-causing organism entering a population e. an increase in the total rainfall in a normally dry environment