There aren't enough oxygen molecules in the air are higher altitudes
Answer:
Skeletal system
Explanation:
the bones of the skeleton protect the internal organs and reduce the risk of injury on impact. For example, the cranium protects the brain, the ribs offer protection to the heart and lungs, the vertebrae protect the spinal cord and the pelvis offers protection to the sensitive reproductive organs.
4. nucleoid region
Bacterial cell's do not have a nucleus; their DNA is found in this region.
Answer:
Declining populations of phytoplankton, the basis of the marine food chain, will alter the seawater hues, potentially decimating fisheries. The world's oceans are warming and growing more acidic as a result of climate change, and a provocative new study suggests they'll be changing color too.
Explanation:
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