Four of the five answers represent events that occurred when free oxygen (O2) became available in the atmosphere. Select the exception
a. aerobic respiration emerged.
b. some organisms changed their metabolism.
c. some species that could not detoxify free radicals became restricted to the low-oxygen environments that remained.
d. oxygen was toxic to many species and some cells and forms of life became extinct.
e. photosynthesis was no longer a common form of energy production.
e
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The lipopolysaccharides are associated with the
a. outer membrane of Gram-positive bacteria. b. outer membrane of Gram-negative bacteria. c. plasma membrane of Gram-positive bacteria. d. plasma membrane of Gram-negative bacteria. e. plasma membrane of both Gram-positive and Gram-negative bacteria.
During implantation, the __________ buries itself in the uterine wall
ANSWER: blastocyst Fill in the blank(s) with the appropriate word(s).
Which of the following is NOT dependent on
the others as a source of food? a. carnivores b. herbivores c. producers d. detritivores e. decomposers
During the first four days of development following fertilization, cells of the embryo undergo rapid cleavage, but the size of the embryo remains the same
Indicate whether the statement is true or false