C. elegans embryo uses both autonomous and conditional modes of specification. The following statements are about specification of cell lineages:

A. The signals from the P1 blastomere instruct the EMS cell for its further development.
B. In the absence of the instructive signal, the EMS cell will divide into two MS cells.
C. In the absence of the POP-1 signal, the progressive cell will take up the E fate.
D. The MOM-2 protein from the blastomere neighbouring the EMS cell instructs the dividing EMS blastomere to take up MS fate.

Which one of the following options represent both correct statements?

Correct option is B

Explanation-

A - The signals from the P1 blastomere instructs the EMS cell for its further development.
Incorrect
The P2 blastomere (not P1) provides Wnt signaling that instructs the EMS cell, especially to form the E cell (endoderm). The P1 cell gives rise to P2, but is not directly responsible for EMS specification.

B - In the absence of the instructive signal, the EMS cell will divide into two MS cells.
Correct
Without the inductive signal from P2, the EMS cell produces two MS-like cells — i.e., endodermal fate is not specified. This shows conditional specification via inductive signaling.

C - In the absence of the POP-1 signal, the prospective MS cell can take up the E fate.
Correct
POP-1 is a Wnt pathway transcription factor. In normal conditions, POP-1 is high in MS (promoting MS fate) and low in E. If POP-1 is absent or reduced, MS may transform into E fate — indicating its role in repressing endodermal genes in MS.

D - The MOM-2 protein from the blastomere neighbouring the EMS cell instructs the dividing EMS blastomere to take up MS fate.
Incorrect
MOM-2 is a Wnt ligand from the P2 cell, but it instructs the EMS to adopt E fate, not MS.
Thus, MOM-2 helps induce E fate, not MS.

Correct Statements: B and C

So, the correct answer is option b - B and C