The heart is a muscular organ that pumps blood around your circulatory system. The circulatory system is the heart and all the blood vessels in the body which carry cells and substances to all its ...

Veins between two capillary networks are portal systems. Closed circulatory system, but fluid constituents of blood leak out of capillaries and return to the heart by the second component of the ...

This article was originally published with the title “ The Circulatory System of Plants ” in Scientific American Magazine Vol. 200 No. 2 (February 1959), p. 44 doi:10.1038 ...

A team of researchers reconstructed a critical ocean current system — called the Atlantic Meridional Overturning Circulation, or AMOC — in computer models and found no evidence of long-term weakening ...