What are examples of conjunctions in a sentence?

Conjunctions are highlighted in the sentences below:

• We bought pencils and notebooks.
• They visited New York City and Washington, DC.
• He plays Baseball and soccer.
• Please bring cookies or cupcakes.
• He wants to be a dancer or an artist.
• She has Allergies or a cold.
• She went to work, but she doesn't feel well.
• He doesn't like school, but he's a smart kid.
• The teacher is kind but firm.