The hepatic portal vein carries blood from which organ to the liver?

$A$ portal system is a system in which

How is the hepatic portal system formed?

Given below are two statements regarding the circulation of blood in fishes.
Statement $I$: The heart of a fish contains only deoxygenated blood.
Statement $II$: Fishes show single circulation,and blood passes through the heart only once during each cycle.
In light of the above statements,choose the correct answer from the options given below.

The circulatory pattern,in which blood pumped by the heart passes through large vessels into open spaces or body cavities called sinuses,is called $.......$ and it is found in $........$

Hepatic portal system is present in