Q: Fact 1: Endocrine hormones travel throughout the body in the blood. Fact 2: Endocrine cells secrete hormones. Given the two facts above, cells that secrete hormones travel throughout the body in what?

Available options: I. skin. II. deltas. III. blood. IV. atoms. V. waves. VI. sleep. VII. genes. VIII. breathe.
A:
III.