How does transcription factor D establish the top of the top-bottom axis of developing flies if it is present in similar numbers in all cells? O Ca++ moves from bottom to top in flies O Another signal...

Extracted text: How does transcription factor D establish the top of the top-bottom axis of developing flies if it is present in similar numbers in all cells? O Ca++ moves from bottom to top in flies O Another signal causes it to move into the nucleus only in top-defining cells O Its target genes are only in cells that establish the top of the fly O Promoters of transcription factor D are unique to cells that establish the top O ATP is only available in cells that establish the top of the fly