Which statement is true regarding the three phases of the life span?

The statement that the longer one lives, the more years are expected, is true and reflects a concept known as "mortality selection" or "survivor bias." This principle indicates that as individuals reach older ages, they have already survived to that point against the factors that typically contribute to mortality. Consequently, those who remain in older age brackets are generally healthier and more resilient, often translating to a longer expected lifespan moving forward. This understanding is vital when discussing aging populations and life expectancy trends, particularly for seniors.

While the other choices present statements related to mortality at various life stages, they do not capture the same demographic insights. For example, mortality is often highest in infancy and old age, rather than being lowest during childhood. The increase in death rates after age 100 can be quite significant, but this statement does not reflect broader statistical trends compared to the notion of prolonged life expectations. Young adults typically have lower mortality rates than older adults due to fewer chronic health issues, further emphasizing the uniqueness of the correct statement about living longer.