profound gaps

"Profound" can mean "deep" or "unfathomable" (which, in turn, means you can't see or understand it). "Profound gaps" are gaps, or empty spaces, in the scientists' knowledge that are so deep that no-one can even guess the answers.

Is "gap" an abstract noun? Why is it plural?

And so "profound" can modify abstract noun and common noun(how to say a common noun, not an abstract one?) ?

I'm not sure what an abstract noun is by definition and I'm not about to look it up right now, but 'gap' is being used as an abstract concept here...there is not LITERALLY a hole, but the missing knowledge can be thought of as a kind of hole..."gap" is not plural, but the quote uses "gaps" which is plural because it has an S at the end...

Sure, any adjective can be used to modify any known as far as I know.

..."gap" is not plural, but the quote uses "gaps" which is plural because it has an S at the end...


So I will wait and see. Thank you very much.

"Gaps" is plural because there are many of these gaps - that is, there are many things we do not know about the Great White.

It implies that our knowledge of these sharks is made up of little pieces of information - with many other pieces missing. Imagine a jigsaw puzzle with some individual pieces in place, and other sections of the puzzle with a few pieces in place, but with many parts of the puzzle still without any pieces at all.

"Profound gaps" implies that many aspects of the life of the great white are totally mysterious to us - that we have not even a glimmering of knowledge - the depth analogy is a good one:

" profound [pro·found || prə'faʊnd]

adj. of great depth, fathomless; deep, not superficial; intense, extreme; serious, sober "

It is appropriate for a sea creature - imagine that these gaps are places where no light penetrates the ocean, where we are blind.

Very clear. Thank you for your helpful information.
And so I think it's an abstract noun since there are no gaps touchable.