Hox genes and other homeobox-containing genes are fundamental to the spatial and temporal control of embryonic development in multicellular organisms.

Consider the following statements regarding homeobox genes and their functions:

1: The highly conserved 180-base-pair homeobox sequence translates into a 60-amino-acid homeodomain that folds into a specific shape to bind directly to target DNA sequences. 2: Hox genes exhibit colinearity, meaning the physical linear arrangement of the genes along a chromosome matches the spatial expression pattern of these genes along the anterior-posterior axis of the developing embryo. 3: Homeobox genes function by encoding systemic signaling molecules, such as peptide hormones, which are secreted into the bloodstream to trigger signal transduction pathways in distant tissues.