A.
The target cells move to one of the poles to establish the anterior-posterior body axis.
B.
The target cells undergo changes in gene expression, sending them down a specific developmental path.
C.
The target cells stop dividing so the neighboring cells have time to get to the same stage of development.
D.
The target cells activate a collection of miRNAs to accelerate transcription and cell division.
The correct answer is B. The target cells undergo changes in gene expression, sending them down a specific developmental path.
To arrive at this answer, we need to understand the process of cellular development and differentiation. During development, cells undergo a series of changes in gene expression, which determines their fate and specialization. This process is driven by specific signals and cues in the cellular microenvironment.
Option A suggests that the target cells move to one of the poles to establish the anterior-posterior body axis. While cell movement is essential during development, it does not directly address the changes in gene expression that determine cell fate.
Option C suggests that the target cells stop dividing to allow neighboring cells to catch up in development. While it is true that cells may temporarily pause their division to synchronize with their neighbors, this alone does not determine their developmental path.
Option D suggests that the target cells activate a collection of miRNAs (microRNAs) to accelerate transcription and cell division. While miRNAs have a role in gene regulation and can influence the rate of transcription and cell division, this option does not address the changes in gene expression that specifically direct the cells towards a specific developmental path.
In contrast, option B correctly explains that the target cells undergo changes in gene expression, which send them down a specific developmental path. These changes in gene expression can be influenced by various factors such as signaling molecules, environmental cues, and interactions with neighboring cells. Ultimately, these changes determine the fate and specialization of the cells.