A mature human being is ______ susceptible to radiation-induced biological changes than a child.

A mature human being is less susceptible to radiation-induced biological changes than a child due to several factors related to biological development and cellular activity.

Children are in a phase of rapid growth and development, which includes high rates of cell division and differentiation. During these processes, cells are more sensitive to various types of stress, including radiation exposure. High cellular turnover means that a child's cells are actively dividing, making them more vulnerable to the effects of radiation at the cellular level, which can lead to a higher risk of mutations and subsequent health issues.

In contrast, adults have already completed most of their developmental growth, and their cells are not dividing as frequently. This lower rate of cell division results in decreased susceptibility to the harmful effects of radiation. Furthermore, mature human tissue has often developed several mechanisms for cellular repair and damage control that may become more efficient with age.

Thus, compared to children, adults exhibit a reduced sensitivity to radiation-induced biological changes, making the conclusion that a mature human being is less susceptible to radiation exposure correct.