One of the strangest features of motherhood is that the vast majority of mothers prefer to cradle their  babies in the left arm. Why should this _____41_____ ? The obvious reason seems to be that the majority of 

mothers _____42_____ right-handed and they wish to keep their right hand free. Unfortunately, this explanation 

 _____43_____ apply, because left-handed mothers also favor their left arm for holding their babies. The precise 

figures are 83 percent for right-handed mothers and 78 percent for left-handed mothers. The most likely reason, therefore, is that the mother’s heart is on the left side and, by holding the baby in her left arm, she is consciously bringing her baby closer to the sound of the heartbeat. This is the sound which the baby heard when it was inside the mother’s body and which is therefore connected to peace, comfort, and security. Tests are carried out in baby’s rooms _____44_____ some babies were played the recorded sound of a human heartbeat, and , sure enough, those babies were caused to sleep twice as quickly _____45_____ the others. We also know that the sound of the mother’s heart is able to be heard clearly inside the body and that the unborn baby has well-developed hearing.