Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Why the lateral hearts have 4 pairs of valves while latero-esophageal hearts have only 3 pairs of valves?
In lateral oesophageal hearts valves are present at the opening of dorsal blood vessel, supra-oesophageal blood vessel and ventral blood vessel. Whereas this is not the case in the lateral hearts. If you think that the valves have to be present only at junctions. The lateral hearts should contain only two pairs of valves at the junction between dorsal blood vessel and ventral blood vessel. But the lateral hearts have 4 pairs of valves. Why? (This is about Pheretima Posthuma (earthworm))
1 Answer
- 1 decade agoFavorite Answer
the answer to this question makes me to ponder about one important point, in closed blood vascular system , no doubt it first time manifested in anilleda , there is a reversal of blood flow isnt it ? hence the arrangement may be like that
