The EXACT question is "cannot be explained with science" - science can be used to EXPLAIN anything. He is not asking for science to prove anything, just to explain it. As that goes he also did not specify a specific study of science. Physics, Biology and Sociology combined can explaint anything (although the answers will be different in each one.)
GOD - This is the reaction to the natural desire to bring value to this world by placing faith in something more than this world. - this could be an acceptable psycology answer (though not well thought out I admit.) Psycology is a science and therefore GOD is explained - NOT PROVED, but explained. As there is no evidence of GOD the explination of the belief would work in this case.
WHY - why is not actually a scientific question. A rock exists simply because it does, if you ask "Why does the Rock exist" you are asking more of a philisophical question and straying very close to religion and the universe having a "sentient purpose." Science does not require a purpose for something to exist, they only want to know how, not why.
Also to be even more specific - the question is not "Is there an intelligence behind the universe" but "How can science explain INTELIGENCE?" The question again is if Science can EXPLAIN something.
This is a loaded question. There is NOTHING that science cannot explain. There is NOTHING that science can PROVE, but the entire scientific community is based off of "Theory" and NOT Truth. Everytime we name a "Truth" our science evolves and that "Truth" suddenly becomes relative to a specific environment and not true outside it.
Thanks