He's growing up, his appetite is increasing, he's becoming embarassed of Scout's company in public, he no longer wants to play... The list goes on and on. It's made very clear in the first few paragraphs there in Book Two (that is, the second part of the story, like Part II)
'Master Jem' is what Calpurnia starts calling Jem once he turns twelve and begins to start spending more time in his room, participating in adult conversation, telling Scout to act like a girl and becoming more grown up.
The two small cakes are for Scout and Dill because they are still young and small. The big cake is for Jem because he is growing and maturing. It's kind of like finally getting to eat at the adult table instead of the kids table during holiday feasts. Jem is becoming a man.
ADONIS
When Miss Maudie says that Jem gets more like Jack Finch every day, she is implying that Jem is becoming more mature, responsible, and thoughtful - traits that are characteristic of his Uncle Jack. It suggests that Jem is growing into a respectful and wise young man, similar to his uncle.
Others in Maycomb generally view Jem with respect because he is seen as a well-behaved and responsible young man. He is also admired for his bravery and calm demeanor during challenging situations. Overall, Jem is held in high regard by his community.
10 to18
Neil Young does not have a song called 'Man of War'. The song 'War of Man' is from the album 'Harvest Moon'.
Scout realizes that the man who saved Jem is Arthur "Boo" Radley. She says, "Hey, Boo." Scout thanks him for saving Jem and silently acknowledges his kindness.
The Greek for "young man" is kouros. (Kouroi, plural.) Another term is ephebe - this relates to a young man that is on the cusp on manhood.
Amitabh Bachchan
That he is a man of many talents.
Jem imitates the man in Atticus's story by standing up to Bob Ewell and defending his sister Scout, showing his courage and sense of responsibility.