Recall the classic experiments that Charles Keeling performed at Mauna Loa (Figure 25.1). What did Keeling's research reveal about atmospheric CO2 levels?
A. that atmospheric CO2 levels fluctuate
seasonally
B. that atmospheric CO2 levels are lowest
during the spring
C. that atmospheric CO2 levels remain
constant throughout the seasons
D. that atmospheric CO2 levels have
decreased over the last 50 years
E. All of the answers options are correct.
A
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What is the function of adenylyl cyclase?
A. to form protein kinase A B. to phosphorylate protein kinase A C. to form cyclic AMP D. to phosphorylate cyclic AMP
According to the endosymbiont theory, host archaea engulfed ___, which then allowed both populations to survive together.
A. photosynthetic archaea B. photosynthetic bacteria C. anaerobic bacteria D. aerobic bacteria E. aerobic archaea
The domains that contain prokaryotes are
A. Archaea, Bacteria, and Eukarya. B. None of the answer choices is correct. C. Archaea and Eukarya. D. Archaea and Bacteria. E. Bacteria and Eukarya.
In an experiment testing the efficacy of cough syrup Brand X, researchers selected 500 participants for the study, and created a control and a placebo group. For this experiment to be considered controlled, a criterion is that:
A) the groups must contain a large number of participants to ensure statistical significance. B) no variation exists among the control group. C) no variation exists among the 500 participants. D) the variation between the participants is randomly divided into the two groups. E) the researchers must never know the group in which the participants are included.