Q--Could Christopher Walken enlist in the United States Marine Corps?
A--My step-by-step reasoning: Christopher Walken is 77 years old. The maximum age for first-time enlistment in the United States Marine Corps is 28.
So, the answer is no.

Q--Is a fever cured by listening to a cowbell?
A--My step-by-step reasoning: A fever is an increase in body temperature above the normal range. Fever can be treated with medication or will usually disappear if left alone. A cowbell is a musical instrument.
So, the answer is no.

Q--Did the Nepalese Civil War take place near India?
A--My step-by-step reasoning: The Nepalese Civil War happened in Nepal. Nepal is a country that shares a border with India.
So, the answer is yes.

Q--Could amoebas have played a part in the Black Death?
A--
My step-by-step reasoning: The Black Death is a bacterial disease called bubonic plague. Yersinia pestis has been found to grow and thrive inside amoebas. Bubonic plague is caused by Yersinia pestis.
So, the answer is yes.