Question

advances in which area are critical in attaining the age of viability?
neurological functioning
sensory development
kidney functioning
weight gain

Explanation:

The age of viability is when a preterm - born baby has a chance of survival outside the womb. Weight gain is crucial as it indicates overall growth and development, and a certain level of weight is necessary for the baby to be able to maintain body temperature, have enough energy reserves, and support organ function. While neurological, sensory, and kidney functioning are important, weight gain is a more fundamental and critical factor in reaching the age of viability.

Answer:

weight gain