The correct answer is C.
An author's credentials can determine a health source's credibility. None of the other options would apply to credibility. When it comes to health, if you want to make sure that what you are researching or reading is authentic and reliable you need to find out whether the author is a professional health expert or not. You can do this by finding out their credentials.
Answer:
Breathing is affected in higher altitudes for several reasons. One is that there is less oxygen. This makes it so less oxygen gets into your lungs. Another reason is that the air becomes cooler and drier. This can affect asthma.
Explanation:
Answer:
C. choosing which players should be substituted
I would pick b, but I would also just ignore it a little too.