Colons and Semicolons

Is the red portion of the text an incomplete or complete thought: Mr. Filch fed his dog a treat; it wagged its tail happily.

Is the red portion of the text an incomplete or complete thought: Until I learn how to braid hair, Andy won't let me work at his barber shop

Is the red and blue text 1 or 2 complete thoughts: I accidentally dropped my bowling ball on Simba's foot; he still let me play, nonetheless

Is the red and blue text 1 or 2 complete thoughts: Sarabi, conversely, doesn't like chocolate-covered strawberries.

Is the red and blue text 1 or 2 complete thoughts: Harry Potter, meanwhile, painted on his canvas in class.

Which punctuation should go between the red and blue text? The stamps in Katniss Everdeen's collection are of great quality _they are also hard to find.

Which punctuation should go between the red and blue text? Some of the volunteers cared about the cause _others were just hoping to impress Jimmy.

Which punctuation should go between the red and blue text? My plan was straightforward _walk right up to Mickey Mouse and ask for his autograph.

Which punctuation should go between the red and blue text? This is the problem _ we need Marty's phone to record the video.