Final answer:
Complex cognitive tasks and physical exercise can help older adults maintain cognitive function and reduce the incidence of neurological decline, thereby combatting cognitive impairment and dementia.
Step-by-step explanation:
Engaging in complex cognitive tasks is indeed beneficial for older adults, and it can act as a defense against some aspects of neurological decline associated with aging. Research indicates that older adults who partake in mentally stimulating activities experience less cognitive decline and might have a lower incidence of mild cognitive impairment and dementia. These activities contribute to maintaining crystallized intelligence (knowledge from life experience), which may remain steady or even improve through aging, whereas fluid intelligence (information processing abilities, reasoning, memory) tends to decline. Nevertheless, physical and mental activities can help delay the onset of this decline. Furthermore, physical exercise is particularly beneficial, as it not only supports the preservation of cognitive function in older adults but also can reduce the risk of developing neurodegenerative disorders such as dementia.