What components of the introns of nuclear genes that encode proteins in higher eukaryotes are conserved and required for the correct excision of intro sequences from primary transcripts by spliceosomes?

The introns of protein-encoding nuclear genes of higher eukaryotes almost invariably begin (5') with GT and end (3') with AG. In addition, the 3'subterminal A in the “TACTAAC box” is completely conserved; this A is involved in bond formation during intron excision.

an adaptation is a change or process by which an organism takes to be better suited for its environment. for example; migration is a behavioral adaptation, this is needed because birds are not built to last extremely cold climates. there are different adaptations because there are different species needing to adjust to different things, bears don't migrate; they hibernate.

the answer is golgi apparatus