<b>Laid end to end</b>, there are 161,000 km of blood vessels in an adult's body. That's enough to <b>circle the world at the equator</b> four times.<br/><br/><b>(If blood vessels were to be)</b> Laid end to end ... That's enough to <b>circle the equator of the ear</b>th four times.<br/><br/>Hi,<br/><br/>The second is how I interpret the first in the above? Correct me if I am wrong. Thanks.