Answer :
Answer: The rising and setting of the Sun.
The appearance and disappearance of the Moon.
Changes in season.
Appearance and disappearance of the Stars.
Explanation: The rising and setting of the Sun helps can be used as a standard to determine time since the rissing and setting of the Sun occurs at similar time and interval in a given geographical ocation.
The appearance and disappearance of the Moon which occurs during the night and early hours of the morning is similar in a given geographical locationation so it can be used as a standard for Time.
Change in season is another natural phenomenon which occurs at similar times in a given geographical location like Winter/summer, rainy/dry etc can be used as standards for time.
The appearance and disappearance of the Stars can also b used as standards for time in a given geographical location.