Final answer:
While not explicitly stated, substances released from microtubules may relate to the organization of the inner cell mass into the germ layers ectoderm, mesoderm, and endoderm during gastrulation in embryonic development.
Step-by-step explanation:
The substances released from microtubules in the future dorsal one-third of the 1-celled embryo are important for the establishment of the embryonic axes during development. These substances are not explicitly mentioned in the question, but the context suggests they could relate to factors that contribute to the organization of the inner cell mass into germ layers during early embryonic development.
During the gastrulation phase of embryonic development, the cells of the blastula rearrange themselves to form three germ layers: the ectoderm, mesoderm, and endoderm. These layers further differentiate into various organ systems. For instance, the ectoderm gives rise to the nervous system and epidermal skin cells, the mesoderm to muscle cells and connective tissue, and the endoderm to the internal organs. However, the trophoblast, which is mentioned in the context of a blastula, is part of the outer layer that eventually forms part of the placenta, not a germ layer.