Mr. M, a 72-year old male, has a history of aortic stenosis.  The last Echo, 6 months ago, showed worsening of the stenosis but the cardiologist told him he is not yet a candidate for surgery. He presents to his primary care NP for his 6 month chronic disease checkup.  The NP asks the patient if he is having what symptoms that would indicate the stenosis has reached a critical point requiring surgery? 

A diagnosis of functional somatic syndrome is associated with all of the following except: 

Why is it difficult to breathe at high elevations, especially without prior acclimation?

The two laboratory tests, that when abnormal, indicate worsening hepatocellular function are 

Which of the following statements is true about the Permian-Triassic mass extinction event?

Under the Clean Air Act, concentrations of criteria pollutants are monitored ____.

Which of the following is an amplifying/positive climate feedback?

This Southern Ocean keystone species is at particular risk from climate change, potentially triggering a cascade of impacts throughout the entire food web.

The combustion of ____ releases less air pollution and greenhouse gas emissions than the other fossil fuels.

Which of the following is an ecosystem function provided by soil ecosystems?