Question 4: the correct answer is 3. Did you get it right? Award yourself 1 point.
Question 5 of 10
What is the fastest land animal over a short sprint?
Why, in question 4: How many hearts does an octopus have?
The answer is 3. Two smaller hearts pump blood through the gills, where it picks up oxygen, and one larger heart sends this blood to the rest of the body.
An animal full of surprises
The octopus can also change its colour and texture in a fraction of a second. Its skin has thousands of pigment cells, which open and close under nerve control, and this serves both to hide and to communicate.
With no bones at all, the octopus's body can squeeze through surprisingly small gaps. The only hard part is the beak, which resembles a parrot's, and it is the beak that determines the smallest hole through which the animal can pass.
Octopuses are among the most intelligent invertebrates known. In the laboratory they have opened jars with screw-top lids and learned to solve simple mazes, and in the sea there are octopuses that carry coconut shells to use as shelters.
Most octopuses live only one to two years. After laying their eggs, the female stops eating and spends the following weeks guarding them, cleaning them and blowing fresh water over the clutch until the young hatch.
