The tense is present simple as in expressing a fact or permanent situation - "Who likes science." Who is 3rd person singular. I like science. They like science. We like science. She/he likes science.

Yes "who" conjugates just like "he". Who is Who has Who does Who wants etc.

我个人觉得，虽然是对着全班的人询问，其实我们还是问的“谁（哪个人）喜欢科学”。因此可以用单数likes，我一般不太会问“谁（哪些人）喜欢科学”。从这个角度来说，我觉得who做主语时，动词用第三人称的可能性最大，不管回答是一个人还是多个人，不影响问话中的动词用单数。而象who are they?这里的主语因为不是who,而they，因此，这里的who理论上说等于they，但就是汉语“他们是谁”，也很难说“谁”成了复数。要表达复数似乎也要说成“他们是些什么人？”。 我的意思“谁”似乎总是单数，那who做谁讲的话，似乎也应该是单数。不知道对不对。

'Who likes science ?' is correct. Answer > can be only 1 person or more like science From the net: In general, the interrogative pronoun "who" takes the default value of singular; and when it does take the value of singular, its question can allow both singular and plural answers. If the speaker doesn't really know whether the answer will be singular or plural, or is willing to expect either a singular or plural answer, then the speaker will (in general) use the default singular for their question: