#Question id: 9161
#Unit 9. Diversity of Life Forms
When climbing a mountain, we can observe transitions in biological communities that are analogous to the changes ________.
#Question id: 10961
#Unit 7. System Physiology – Animal
Over the past 12 weeks, a 75-year-old man with a moderate aortic stenosis has developed shortness of breath and chest pains during exertion. He appears pale. Test of his stool for blood is positive. Laboratory studies show the following: hemoglobin 7.2 g/dL, and mean corpuscular volume 75. A blood smear shows microcytic, hypochromic erythrocytes. Which of the following is the most likely diagnosis?
#Question id: 12223
#Unit 10. Ecological Principles
#Question id: 11454
#Unit 7. System Physiology – Animal
The structure of the mammalian middle ear is adapted to convert ________.
#Question id: 1239
#Unit 4. Cell Communication and Cell Signaling
GTPases serve in many signal transduction pathways and the presence of GTP or GDP dictates whether the pathway is on or off, respectively. Which of the following statements is TRUE regarding guanine nucleotide exchange factors (GEF) and the role in these signaling pathways?