In late adulthood, changes in memory may bot be inevitable however, any decline in memory tends to invite

I believe the answer is Episodic memory
Episodic memory refers to a collection of one's  experience at a certain time, place, or date.
In late adulthood, our brain capability to recall information from episodic memory is heavily impaired, and make older people tend to forget things a lot faster compared to the younger ones.

This is the answer: body 1 + engine 2

It equals just about 6,300 km per hour each day an week