Final answer:
Anders, in his mid-fifties, can expect decreases in stamina, strength, reflex times, and sensory abilities as he ages, along with cognitive changes and a less efficient immune system.
Step-by-step explanation:
Anders, being in his mid-fifties, can expect a gradual decrease in several physical and cognitive abilities as he transitions into old age. This includes a decline in stamina, strength, reflex times, and sensory abilities such as vision and hearing. Additionally, cognitive changes like a decrease in brain cell numbers and reduced efficiency of the immune system are common, increasing the risk of illnesses and conditions such as Alzheimer's disease. It's important to note that while these declines are common, there is considerable individual variation in how and when they manifest.