Which of the following statements about the removal of introns is correct? spacer dna is removed from primary transcripts at the same time as introns. if introns are not removed by snrnps, catalytic ribosomes are also able to recognize the coding sequence and can cleave out the introns. introns are removed in the nucleus prior to the export of the mrna into the cytoplasm. although the number of introns to be removed can vary from gene to gene, the size of the excised introns is approximately equal from gene to gene. since snrnps cleave in the interior of the primary transcripts to remove introns, this is an example of exonuclease activity.