Answer:
Responses may vary but should include some or all of the following information:
Negative reinforcement encourages a behavior by removing an unwanted or unpleasant stimulus. Positive punishment discourages a behavior by introducing an unwanted or unpleasant stimulus.
The blood brings oxygen to the body cells<span> and takes away their carbon dioxide. The blood that travels </span>back<span> to the </span>heart<span> and </span>lungs<span> is </span>dark red<span>. It has picked up carbon dioxide from the </span>body cells<span>, and it has left most of its oxygen with the cells.
</span><span>http://lsa.colorado.edu/essence/texts/lungs.html
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