<span>The heat comes from the outer core, which provides the heat.</span>
Answer:
the common thing is they all give birth to young ones and they are called mammals.
hope it helps....
Answer:
they form to combine an organ system
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.
