Approximately two billion years ago, ________ were primarily responsible for initially oxygenating Earth
A) algae
B) Archaea
C) cyanobacteria
D) purple sulfur bacteria
Answer: C
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During strenuous exercise, you may notice that your muscles burn. Which of the following statements best explains this phenomenon?
A) Proteins are being digested to provide energy. B) Carbon dioxide is building up in muscle and changing the pH. C) Without oxygen, pyruvate is being converted to lactic acid. D) ADP is accumulating, which produces a burning sensation. E) Pyruvic acid causes muscle pain.
Which is a benefit of sexual reproduction over asexual reproduction?
a. More offspring can be produced. b. The offspring are all identical to the parents. c. There is less variation from generation to generation. d. Evolution will occur at a slower rate when there are two parents. e. The interaction of the genes from both parents brings about genetic variation.
There are cases, particularly in fruit flies, in which a normal body part grows in the wrong spot. For instance, legs on the head growing instead of antennae, or a second set of wings behind the normal pair. What can explain this?
A. These are due to misregulation of hormones from environmental contamination with pesticides. B. These naturally occur sometimes in animals that have metamorphic development, due to different organization of homeotic gene expression in larvae versus adults. C. These occur as a result of mutations in homeotic genes, which normally act to direct development along the anterior-posterior axis. D. These are due to the reappearance of stem cells, which are totipotent.
The observation that different geographical areas sometimes exhibit plant and animal communities of similar appearance, even though the individual plants and animals are not closely related, is called
A. homology. B. adaptation. C. the fossil record. D. convergent evolution. E. divergent evolution.