Which of the following is a characteristic of amniotic fluid?

Amniotic fluid serves several crucial functions during pregnancy, one of which is to allow for fetal movement. This fluid surrounds the fetus, creating a cushion that not only protects the developing baby from injury but also enables it to move freely within the amniotic sac. This movement is essential for muscular and skeletal development, as it allows the fetus to exercise its limbs and engage in natural movements that contribute to overall growth.

The other functions of amniotic fluid, while important, do not focus on the specific nature of enabling movement. For instance, while promoting lung development is a function of amniotic fluid, this primarily refers to the fluid being inhaled and exhaled by the fetus, facilitating the growth of lung tissue. Similarly, while there may be implications on temperature regulation due to the insulating properties of the fluid, the primary characteristic of allowing movement stands out as a key benefit for fetal development. Thus, the ability of amniotic fluid to provide an environment conducive to movement is a distinctive and vital characteristic.