Final answer:
Mesenchyme is the embryonic connective tissue that adult connective tissues, blood, and blood vessels are derived from.
Step-by-step explanation:
The embryonic connective tissue that adult connective tissues, blood, and blood vessels are derived from is Mesenchyme. Mesenchyme is the stem cell line from which all connective tissues are later derived. It is present in the embryo and later develops into various types of connective tissues in the adult body, such as bone, cartilage, and blood.