The hollow<span> part of a </span>bird bone<span> isn't wasted space. In some </span>bones<span>, the </span>hollow<span> cavities contain extensions of the air sacs from the lungs. These air sacs help the </span>bird<span> to get the oxygen it needs to fly quickly and easily.</span>
C. plants don't need oxygen, they need carbon dioxide and PRODUCE oxygen. Animals DO. Need oxygen, I mean.
Answer:
<h3>Seafloor sediment consist mostly of terrigenous sediment, biogenous sediment and hydrogenous sediment. Terrigenous sediments form from sediments carried from the land into the ocean by water, wind or ice.</h3>
Answer:
oxygen enters blood cells by 'diffusion'
