There are two explanations I can think of:

1) it is very literary sometimes to use "ne" without "pas" in negations.2) it is a mistake and it should be there.

Thanks Chris. I know that in the “ne ... pas” construction for negation the “ne” is optional and is very rarely used in conversation, but I thought the “pas” was essential because without it you are entering into the treacherous “ne explétif” territory of C1 quizzes, where the ne has no meaning and is essentially the opposite of ne pas. On reflection I wondered if “même” with “ne” meant “not even”, but I can find nothing to back up this hypothesis. But if that was so, then the sentence could literally be translated as “not even scientists can predict the future” as opposed to “even pharmacists can not predict the future”. Or then again maybe your second hypothesis (it’s a mistake) might be the correct one! 

Here is some information on the so-called "ne litteraire": https://www.lawlessfrench.com/grammar/ne-litteraire/

It does seem, however, that it is only used in very specific circumstances.

Thanks Chris. I have not come across this before, and it seems that pouvoir is one of the cases that the "ne litteraire" can be used, so it does appear they have gone literary with this particular quizz question. Thanks again for your explanation and the link.