How blood circulate?

Answer 1

The heart pumps it.

I searched Google under the key words "blood circulation" to get these possible sources:

https://www.google.com/search?client=safari&rls=en&q=Blood+circulation&ie=UTF-8&oe=UTF-8

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.

http://www.hackcollege.com/blog/2011/11/23/infographic-get-more-out-of-google.html

Answer 2

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072434/