a. According to Shakespeare, all the world is a stage because life itself is a drama. We are born, we live, and we die. Each life event is a scene in a universal play.

b. 'Exits' and 'entrances' are compared to birth and death in life. An entrance signifies our birth or arrival into the world, and an exit signifies our death or departure from the world.

c. The phrase "one man in his time plays many parts" means that as individuals, we carry out and perform various roles throughout our lives. In different phases of life, we are a child, a student, a professional, a spouse, a parent and so on.

d. It is understood to be death or the end of life's journey, as Shakespeare’s seven ages of man ends with extreme old age and returning to infancy and eventual death.

e. "Plays many parts" refers to the many roles and characters we assume throughout our lives. Depending on our age, circumstances, and relationships, we take on different roles and responsibilities.

f. The poetic device in the first line is a metaphor. The world is metaphorically compared to a stage, implying that life is but a series of performances.

a. When the poet says, "they have their exits and their entrances," he is using a metaphorical reference to the theatrical World. In a play, actors enter the stage through an entrance and leave it through an exit, and this repeatedly happens as the story unfolds. In the context of this monologue, the poet is suggesting that life is like a play, and people have their entrances and exits into the World. When we are born, we enter the World, and when we die, we exit it. Similarly, throughout our lives, we have many entrances and exits into different experiences, relationships, and phases of life.
b. The phrase "merely players" in the context of this monologue suggests that human beings are not the central figures in the grand scheme of things. Instead, they are just part of a larger play, a metaphorical reference to the world itself. In other words, human life is transient and fleeting, and people are just actors who come and go on the stage of life. Overall, the phrase "merely players" suggests that people are part of something larger than themselves and that they should not take themselves too seriously.
c. Shakespeare divides human life into seven stages or acts in the monologue "All the world's a stage" from his play "As You Like It". The seven acts are as follows: Infant: In this stage, a person is born and is entirely dependent on others for survival. Schoolboy: The second stage begins when the child enters school and begins to learn about the world. Lover: In the third stage, the person experiences the joys and sorrows of romantic love. Soldier: The fourth stage sees the person enter into adulthood and become a soldier, risking their life in battle and seeking honor and glory. Justice: In the fifth stage, the person becomes an elder and seeks to impart wisdom and justice to others. Pantalone: In the sixth stage, the person becomes elderly and nostalgic, reminiscing about their youth. Second Childhood: In the final stage, the person becomes frail and dependent, losing their teeth, eyesight, and taste, and eventually, their life.

(Reginald): "One goes to the Academy in self-defence," said Reginald, "it is the one topic one has in common with the Country Cousins."

"It is almost a religious observance with them," said the Other. "A kind of artistic Mecca, and when the good ones die they go--"

(Reginald): "To the Chantrey Bequest. The mystery is what they find to talk about in the country."

(the Other): "There are two subjects of conversation in the country: Servants and Can fowls be made to pay? The first, I believe, is compulsory; the second, optional."

"As a function," resumed Reginald, "the Academy is a failure."

(the Other): "You think? It would be tolerable without the pictures?"

(Reginald): "The pictures are all right in their way; after all, one can always look at them if one is bored with one's surroundings or wants to avoid an imminent acquaintance."