0 pairs
up to four pairs is the answer
12 has 3 factor pairs and the pairs are (1,12), (2,6) and (3,4).
It has 6 possible pairs of sides, although all the pairs will look the same. It has 6 possible pairs of angles, although all the pairs will look the same.
There are infinitely many pairs. For example 23.5 and 75.5 or -3 and 102.
South Indian Earthworm is the common name of megascolex. Its scientific name is Pheritima Posthuma.
According to my Snapple cap, The common garden worm has 5 pairs of hearts
Earth worms have 4 pairs of heart. pheretima has 4 pairs of hearts.
An earthworm, Annelida [= ringed] has up to five pairs of hearts.
by the help of the heart
You have 12 pairs of ribs, making a total of 24 ribs in your ribcage. The ribs protect your internal organs like the heart and lungs.
They are pairs of chambers inside the heart, which have valves.
Many, many pairs.
It has 2 pairs.
3 pairs
Six pairs
Two pairs.