They breathe through their skin. Air dissolves on the mucus of their skin, so they MUST stay moist to breathe.
If worms dry out, they suffocate. As fresh air is taken in through the skin, oxygen is drawn into the worm's circulatory system, and the worm's hearts pump the oxygenated blood to the head area.
Answer: Low levels of testosterone has been linked to joint pain and may cause rheumatoid arthritis in the long run. Rapid growth can lead to joint damage as <span>the accelerated bone growth disrupts the supply of blood to the cartilage, causing bone death and regrowth.
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20.4 21.3 are the correct answers
As energy moves through trophic levels in an ecosystem the amount that is available decreases. ... A: Energy flows in a food web by being transferred to and between organisms as they undergo photosynthesis, are consumed by another organism, or decompose.