Which of the following statements about pattern formation are true? Select the four statements that are true.
a. Homeotic genes code for transcription factors that control the development of segment-specific body parts.
b. Homeotic genes establish major body axes.
c. Cells receive molecular signals that communicate their position in relation to other cells.
d. Differential gene expression affects the developmental process in animals.
e. Pattern formation begins in adult animals.
f. The process of pattern formation involves segmentation of the body but does not involve the development of segment-specific body parts.
g. Positional information controls pattern formation.