Final answer:
The line 'And it grew both day and night. Till it bore an apple bright.' is the best example of symbolism, representing the growth of knowledge and understanding.
Step-by-step explanation:
The line 'And it grew both day and night. Till it bore an apple bright.' is the best example of symbolism. In this line, the apple symbolizes knowledge or enlightenment. The growth of the apple tree represents the growth of knowledge and understanding.
Learn more about Symbolism in literature