Final answer:
The two CBC that remain constant from year to year are age, which increases consistently, and location, which remains fixed unless changed.
Step-by-step explanation:
The two CBC (statistical characteristics) that remain constant from year to year are age and location. Over time, someone's or something's age will consistently increase as the years go by, reflecting the passage of time. Similarly, the location, being a geographic or spatial term, can remain constant if it refers to a fixed place such as a city or an address, like a local park or the area around it. Consider the given reference where a study involves the age of park residents and the frequency and duration of park use. Their age will increase each year while the location of their residence relative to the park will remain constant barring any significant changes.