Final answer:
The genes that control development encode for transcription factors, which act as genetic activators to regulate the expression of other genes. These factors are essential for cell differentiation and the proper development by modulating gene expression via binding to DNA regulatory elements.
Step-by-step explanation:
The genes involved in controlling developmental processes code for transcription factors, thus those genes act as genetic activators to regulate the expression of other genes. These transcription factors can either promote or inhibit the transcription of target genes. They perform this action by binding to regulatory elements on the DNA, such as promoters, enhancers, and silencers, to modulate gene expression.
Moreover, these transcription factors are crucial during a cell's differentiation. They decide which genes are to be expressed and which are not, thereby determining the cell's eventual specialized form and function. This process of gene regulation, especially by transcription factors such as activators and repressors, is essential for the proper development of an organism.