Answer:
infancy and old age
Step-by-step explanation:
"All the World's a Stage" is a poem written by William Shakespeare. This portrays the life of people according to their roles in the society and how their roles relate to that of actors. People start assuming these roles from the time they were born, to the time they reach old age.
"Infancy and old age" are the two ages that share the most similar characteristics. According to the poem, when people get older, they lose their teeth, sense of taste, eyesight, etc. Similarly, infants also have no teeth or poor eyesight at the start. So, this gives off a similarity between the two. The older person also shrinks and becomes weaker, same case with infants who also need the care of people around them.
So, this explains the answer.