Answer:
Shadow.
Step-by-step explanation:
Predicting the time, days, seasons, and directions by studying the shadow is one of the oldest form of predicting the time. Before clock was invented, people used to determine the time of the day, cardinal directions, seasons by studying the shadow formed by the position of the sun.
People can determine the time or what season is it by observing the length of the shadow formed by the position of the sun. People used to determine the time with the help of sundials before the clock was invented. The shadows will be longer at the beginning and at the end of the day and shorter in the middle of the day.
So, the correct answer is shadow.