Answer:
As scientists were unraveling the mysteries associated with transcription and translation in eukaryotes, they discovered there was not a one-to-one correspondence between the nucleotide sequence of a gene and the base sequence of the mRNA it codes for. They proposed the genes-in-pieces hypothesis. How can the genes-in-pieces hypothesis be explained?
I. Exons are noncoding segments of DNA that are not read or transcribed by RNA polymerase
II. Exons are noncoding segments of DNA that are present in the initial transcript, but are removed by splicing.
III. Introns are noncoding segments of DNA that are present in the initial transcript, but are removed by splicing.
IV. Introns are noncoding segments of DNA that are not read or transcribed by RNA polymerase II
THE ANSWER IS
III. Introns are noncoding segments of DNA that are present in the initial transcript, but are removed by splicing.