"their exoskeleton have grown"
This seems to be using the singular "they", which doesn't make sense. It would be best to use the representative "it". (e.g., "A lion uses its claws to pin down prey.")
"Reproductive wise," Reproduction-wise.
"serve as funnels that help to funnel" Using "funnel" twice is awkward, though it's not strictly necessary to remove.
"these opening" (Into these openings)
"have evolved blood. Sort of." This is rather informal. "have evolved a sort of blood" keeps most of the phrasing, but is more formal.
"etc..." There's only one "." in "etc.", and only one period at the end of a sentence, so it should be "..".
"This substance is a yellowish tinge in color"
"Yellowish" and "tinge" are redundant. "This substance is yellowish" or "this substance has a yellowish tinge" is better.
Cobloglobin is a synthetic compound, so it's odd for it to exist within a natural organism.
In any case, since it doesn't exist in nature, I recommend adding a little more detail about how it came to exist in this organism.
Try looking at these sources on coboglobin:
http://www.xenology.info/Xeno/10.4.htm
https://worldbuilding.stackexchange.com/que...n-clarificationhttps://worldbuilding.stackexchange.com/que...-an-alien-blood"liquid, gas". The comma should be a period.
"mall size". That's hilarious, but a typo. You meant "small size".
"bundle several" should be "bundle of several".
Out of curiosity...where are its primitive hearts in its body?