The answer is the last one
Answer:
The answer should be C: mostly in the 20th century
Explanation:
Answer:
<em>At the respiratory membrane, where the alveolar and capillary walls meet, gases move across the membranes, with oxygen entering the bloodstream and carbon dioxide exiting. It is through this mechanism that blood is oxygenated and carbon dioxide, the waste product of cellular respiration, is removed from the body.</em>
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Answer:
B: Polyermase Chain Reaction
Explanation:
PCR is when we take a segment of DNA and multiply it! We can see that the number of DNA segments are increasing therefore it is PCR. Hope this helps!
