Question

which sentences are compound - complex sentences? check all that apply.
your brain produces more dopamine when it is engaged in solving a puzzle.
our brains produce a chemical known as dopamine that is involved in learning and in creating memories.
we can put together a puzzle that has challenging shapes, or we can try to solve the sudoku in the newspaper.
working on puzzles increases our concentration and can expand our creativity; puzzle - making even has health benefits.
students can improve their performance when they are faced with a challenging task, but they will have to start doing jigsaw puzzles.

Explanation:

To determine compound - complex sentences, we need to recall that a compound - complex sentence has at least two independent clauses and at least one dependent clause.

Analyzing each option:

1. "Your brain produces more dopamine when it is engaged in solving a puzzle."

• This sentence has one independent clause ("Your brain produces more dopamine") and one dependent clause ("when it is engaged in solving a puzzle"). So, it is a complex sentence, not a compound - complex sentence.

1. "Our brains produce a chemical known as dopamine that is involved in learning and in creating memories."

• It has one independent clause ("Our brains produce a chemical known as dopamine") and one dependent clause ("that is involved in learning and in creating memories"). So, it is a complex sentence, not a compound - complex sentence.

1. "We can put together a puzzle that has challenging shapes, or we can try to solve the sudoku in the newspaper."

• It has two independent clauses ("We can put together a puzzle" and "we can try to solve the sudoku in the newspaper") and one dependent clause ("that has challenging shapes"). So, it is a compound - complex sentence.

1. "Working on puzzles increases our concentration and can expand our creativity; puzzle - making even has health benefits."

• This is a compound sentence as it has two independent clauses separated by a semicolon. There are no dependent clauses, so it is not a compound - complex sentence.

1. "Students can improve their performance when they are faced with a challenging task, but they will have to start doing jigsaw puzzles."

• It has two independent clauses ("Students can improve their performance" and "they will have to start doing jigsaw puzzles") and one dependent clause ("when they are faced with a challenging task"). So, it is a compound - complex sentence.

• A compound - complex sentence has at least two independent clauses and at least one dependent clause.
• The sentence "We can put together a puzzle that has challenging shapes, or we can try to solve the sudoku in the newspaper" has two independent clauses ("We can put together a puzzle", "we can try to solve the sudoku in the newspaper") and one dependent clause ("that has challenging shapes").
• The sentence "Students can improve their performance when they are faced with a challenging task, but they will have to start doing jigsaw puzzles" has two independent clauses ("Students can improve their performance", "they will have to start doing jigsaw puzzles") and one dependent clause ("when they are faced with a challenging task").
• The other sentences do not meet the criteria of having at least two independent clauses and at least one dependent clause.

Answer:

• We can put together a puzzle that has challenging shapes, or we can try to solve the sudoku in the newspaper.
• Students can improve their performance when they are faced with a challenging task, but they will have to start doing jigsaw puzzles.