<span>The heart contains four chambers: upper left atria, upper right atria, lower left ventricle and the lower right ventricle. Oftentimes, the right atria and right ventricle are together referred to as the "right heart" and the left atria and left ventricle are referred to as the "left heart", however there are still four separate chambers.</span>
That would be integumentary system
Here, you go:
Answer:
<u><em>Generation of B Cells. The immune system is remarkable for its ability to respond to a great many antigens.</em></u>
Explanation:
<u><em>These cells make antibodies which defends and fights out viruses in our bodies.</em></u>
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<em>~Hope This Helps~</em>
I believe its D they decompose wood and other tough materials and then absorb them.
