Final answer:
The statement is true; modifications such as the 5'-CAP, poly-A tail, and splicing occur in the nucleus. These modifications to pre-mRNA are essential before the mRNA is transported to the cytoplasm for translation.
Step-by-step explanation:
The statement that all the modifications to RNA such as the 5'-CAP, the poly-A tail, and the spliceosome take place in the nucleus is true. During RNA processing, eukaryotic pre-mRNAs are modified with a 5' methylguanosine cap and a poly-A tail, which protect the mature mRNA from degradation and help it to be exported from the nucleus. In addition, pre-mRNAs undergo splicing where introns are removed and exons are reconnected. Only after these modifications, including 5' capping, 3' polyadenylation, and intron splicing, is the mature mRNA exported to the cytoplasm. Furthermore, other RNAs like tRNAs and small nuclear RNAs, which are also transcribed in the nucleus, undergo their own specific processing before they function in translation and other cellular processes.