Curious Facts Quizzes / Nature · 3 questions
How do an octopus’s hearts work?
Explore the number of hearts, their roles, and where blood takes up oxygen, one question at a time.
No prior knowledge is needed. Choose an answer to see the explanation and evidence.
1Understanding
How many hearts does an octopus have?
Correct answer: Three
An octopus has three hearts. The next question explores what each of them does.
Evidence: An octopus has three hearts. The key fact at the top of the reading states that an octopus has three hearts.
2Understanding
How do the three hearts divide their work?
Correct answer: Two send blood to the gills; one sends it around the body.
The two branchial hearts send blood to the gills. The systemic heart sends oxygen-rich blood to the body. The three hearts do different jobs.
Evidence: Two branchial hearts push oxygen-poor blood towards the gills. The following reading paragraph identifies the systemic heart as the pump supplying the body.
3Understanding
Where has the blood gained oxygen before reaching the systemic heart?
Correct answer: It took up oxygen from the water at the gills.
Blood takes up oxygen at the gills before reaching the systemic heart. Hearts pump the blood rather than manufacture oxygen.
Evidence: After picking up oxygen at the gills, the blood reaches the systemic heart. The preceding reading paragraph locates oxygen uptake at the gills, rather than inside a heart.
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Connected reading
Do an Octopus’s Three Hearts Do the Same Job?