Final answer:
Frederika likely believes that physical activity is what helps increase Jethro's attention span, as exercise improves cognitive functions by enhancing blood flow, growth factors, and neurotransmitter levels.
Step-by-step explanation:
According to Frederika, what helps increase Jethro's attention span? The reference materials suggest that physical activity is beneficial for improving cognitive processes, which could include increasing Jethro's attention span. Physical exercise has been shown to increase blood flow and oxygen availability to the brain, increase growth factors that promote new brain cells and neural pathways as well as increase levels of neurotransmitters such as serotonin, which aid in memory retention, information processing, and cognition. Given this information, physical activity is an effective approach to enhancing cognitive functions and could be the method that Frederika finds helpful for Jethro.