Free help with homework

Why join Brainly?

  • ask questions about your assignment
  • get answers with explanations
  • find similar questions


Oxygen enters the respiratory system through inhalation and then it enters the bloodstream to be circulated throughout the body . carbon dioxide from the tissues enters the blood, then to the lungs where it is exhaled
4 4 4
The Brain
  • The Brain
  • Helper
Not sure about the answer?
Learn more with Brainly!
Having trouble with your homework?
Get free help!
  • 80% of questions are answered in under 10 minutes
  • Answers come with explanations, so that you can learn
  • Answer quality is ensured by our experts