2. Specify the connective tissue embryonic origin:

The correct answer is: Mesoderm.<br /><br />Connective tissue, which includes structures such as bones, cartilage, and blood vessels, originates from the mesoderm during embryonic development. The mesoderm is one of the three primary germ layers that form in the early embryo, the other two being the ectoderm and endoderm. The mesoderm gives rise to various tissues and organs, including the skeletal system, muscular system, circulatory system, and excretory system, among others.