Answer:
They cross over. Hope this helped
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oxygen
Your cells need oxygen to convert the nutrients you eat into energy for your body. In the process of making that energy, some waste products are produced. One of the main waste products is a gas called carbon dioxide.
I believe it is A. <span>Adenine and Thymine </span>pair with each other
Answer:
High altitude – as altitude increases, the availability of oxygen decreases, making the air thinner and drier. The dryness can cause the nose to bleed.