What does a 'mature content' mean?

example: more than 90% of these games involve mature content that often includes violence

Which sentence in this excerpt from frances hodgson burnett’s a little princess shows indirect characterization? it was just then that miss minchin entered the room. she was very like her house, sara felt: tall and dull, and respectable and ugly. she had large, cold, fishy eyes, and a large, cold, fishy smile. it spread itself into a very large smile when she saw sara and captain crewe. she had heard a great many desirable things of the young soldier from the lady who had recommended her school to him. among other things, she had heard that he was a rich father who was willing to spend a great deal of money on his little daughter. "it will be a great privilege to have charge of such a beautiful and promising child, captain crewe," she said, taking sara's hand and stroking it. "lady meredith has told me of her unusual cleverness. a clever child is a great treasure in an establishment like mine."

Jackson is a very smart little boy he can count to twenty and is only two years old. complete, run on sentence or comma splice

Each pair of sentences can be combined to create one compound sentence. determine which choice best combines them. refinishing furniture is a creative hobby. not everyone loves to scour garage sales to find old items. going to flea markets can you to notice unique qualities in used items. beauty can be found where you least expect it. specialized equipment can make the refinishing process easier. painting the furniture can be creative with the right tools. some people like refinishing old furniture. others prefer buying new items.