Correct option is B
Explanation -
Option a -The specification of primary organizer in amphibian embryo
While important in embryonic patterning, this occurs after fertilization and involves inductive interactions. It is not strictly dependent on the prior specification of a maternal somatic cell.
Not the best match.
Option b - The specification of dorso-ventral axis in Drosophila
This is maternal-effect dependent. Maternal genes (like bicoid, dorsal, etc.) deposited in the oocyte during oogenesis define embryonic axes. This is a classic example where maternal somatic cells (follicle cells) contribute to defining axis formation before fertilization, which then guides embryonic development.
Correct Answer – Option b
Option c - The formation of the vulval precursor cells during development of C. elegans
This is a post-embryonic event influenced by cell signaling, not directly tied to maternal somatic cell fate.
Incorrect
Option d - Specification of the micromeres in sea urchin
While micromeres are important for development, their specification occurs through cleavage and is not directly linked to prior maternal somatic cell fate.
Incorrect
So, the correct answer is option b - The specification of dorso-ventral axis in Drosophila.
