Which of the following is not found in mammals?

Differentiate between: Open circulatory system and closed circulatory system.

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.

How many double circulations are normally completed by the human heart in one minute?

William Harvey is known for the discovery of

Which of the following carries glucose from the digestive tract to the liver?