Some transcription signals are located thousands of base pairs upstream of the gene they regulate. How does the distant signal initiate transcription

enhancer sequences bind to transcription factors to increase the likelihood of transcription  

Explanation:

Enhancers are short DNA regions (50–1000 bp) that may be localized upstream and downstream from the transcription start sites of the gene. It has been shown that enhancers can be localized several kilobases (30-100 kb) either 5' or 3' of the gene. These sequences bind to proteins (generally transcription factors) in order to alter the 3D structure of the DNA, thereby increasing the likelihood of transcription.

the offspring would all be white. if the parents are both white flowers then they have the genotype rr, which when crossed results in an all white punnet square.