Sentence Correction

As a result of the ground-breaking work of Barbara McClintock, many scientists now believe that all of the information encoded in 50,000 to 100,000 of the different genes found in a human cell are contained in merely three percent of the cell's DNA.

(A) 50,000 to 100,000 of the different genes found in a human cell are contained in merely
(B) 50,000 to 100,000 of the human cell's different genes are contained in a mere
(C) the 50,000 to 100,000 different genes found in human cells are contained in merely
(D) 50,000 to 100,000 of human cell's different genes is contained in merely
(E) the 50,000 to 100,000 different genes found in a human cell is contained in a mere


Please explain option D and E . How does mere and merely changes the meaning ?

I would eliminate D more for the construction of 'of human cell's different genes' -- the 50,000 to 100,000 is modifying genes, so it is clearly to have them closer together.

Also, the article 'the' is needed before the numbers

As far as your question:

The difference is in the type of speech.

Merely is an adverb, which typically modifies adjective, verbs, or other adverbs (They can modify nouns in rare circumstances, such as gerunds, but without digressing too far, gerunds take on verb characteristics in sentence structure)

Mere is an adjective, which will modify a noun.


Now, I could argue that merely is modifying three (an adjective) or that three percent is a compound noun. To me a bit tricky to say with certainty, so I revert to the earlier reasoning.