Answer:
They break down the pathogens that enter the body
Explanation:
- Macrophages are the first line of defense .
- They engulf any pathogen that gets in their way in a process called phagocytosis
Phagocytosis
- When the macrophages ingest the pathogen ,the cell membrane surrounds the pathogen to form a vesicle known as a phagosome
- Later this phagosome is combined with a lysosome ,which is a vesicle containing digestive enzymes to form phagolysosome.
- The digest enzymes in the lysosomes breaks the pathogen down.
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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