Final answer:
The Y chromosome contains the SRY gene that triggers embryonic development as a male.
Step-by-step explanation:
The subject of this question is Biology and it is appropriate for High School level students.
The Y chromosome contains a gene called SRY that triggers embryonic development as a male. The SRY gene produces the Testis-determining SRY protein which initiates the development of male sex characteristics.
Without the SRY gene or with a deletion or mutation of the gene, the embryo may not develop into a male, resulting in conditions such as Swyer syndrome where an individual with an XY genotype does not develop into a male.