Sentence:  <WSD>Parabiosis</WSD> is the condition of more than one living organism joined ..., with ... circulatory fluids being exchanged among the parabionts. 
Meaning of the word marked with <WSD> tags:  The (natural or surgical) union of parts of two organisms, especially in such a way as to cause them to share their vascular systems. Organisms so joined then are called parabionts.