Question: The mission of the spliceosome is: 
 Options:  <1> Ensure that the transfer RNAs adopt the trefoil configuration. <2> Prevent ribosomes from entering the nucleus. <3> Perform polyadenylation of messenger RNA (mRNA). <4> Degrade defective proteins. <5> Facilitate the maturation of the mRNA precursor, since it approximates the splice points.
5