How does an import quota differ from an equivalent tariff?

In terms of alternation of generations, the internal parts of the pollen grains of seed-producing plants are most similar to a ) moss sporophyteb) moss gametophyte bearing both male and female gametangiac) fern sporophyted) fern gametophyte bearing only antheridia

What is the one part of the nucleotide  that differs among the other different nucle  tides?

The diagram shows a chicken embryo and a human embryo