You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
Given a paragraph, your job is to generate a question that can be answered from the passage. The answer to your question should be a single entity, person, time, etc. that can be extracted from the passage.

There are a million times more viruses on the planet than stars in the universe. Viruses also harbor the majority of genetic diversity on Earth. Scientists are finding evidence of viruses as a planetary force, influencing the global climate and geochemical cycles. They have also profoundly shaped the evolution of their hosts. The human genome, for example, contains 100,000 segments of virus DNA.
Solution: How many segments of virus DNA does the human genome contain?
Why? The paragraph states the number of segments of virus DNA does the human genome contain, hence the question asked above is appropriate.

New input: Doctor Who has appeared on stage numerous times. In the early 1970s, Trevor Martin played the role in Doctor Who and the Daleks in the Seven Keys to Doomsday. In the late 1980s, Jon Pertwee and Colin Baker both played the Doctor at different times during the run of a play titled Doctor Who – The Ultimate Adventure. For two performances, while Pertwee was ill, David Banks (better known for playing Cybermen) played the Doctor. Other original plays have been staged as amateur productions, with other actors playing the Doctor, while Terry Nation wrote The Curse of the Daleks, a stage play mounted in the late 1960s, but without the Doctor.
Solution:
Who played Doctor Who on stage in the 70's?