The short answer is thatthey do have bone marrow, just not in every bone. Birds bones are delightfully complicated things. Not every bone in a bird's skeleton is hollow. Most of their bones do develop cavities that lesson weight, and are connected to the respiratory system. What do birds ...
Did ancient sharks have bones? No. Fossil evidence suggests that all ancient sharks lacked a true bone-based skeletal system, relying instead on primitive cartilage structures to provide their bodies with support and flexibility. This means that sharks have been without bones for millions of years!
Your skeleton is made of bones.3. All parts of bones are hard.4. Cartilage is harder than bone.5. Cartilage keeps some bones from rubbing against each other.选择最佳答案。1. Human skeletons have overbones!A. two hundredB. two thousandC. four hundredD. three hundred2. Bones areon the ...
1. You cannot see your skeleton because it holds you up from the outside.2. Your skeleton is made of bones.3. All parts of bones are hard.4. Cartilage is harder than bone.5. Cartilage keeps some bones from rubbing against each other.Ⅱ)选择最佳答案。1. Human skeletons have over bones...
Bone marrow, the innermost part of your bones, where new blood cells are made Thymus, a gland behind your breastbone where special immune cells called T-cells are made Lymph nodes (glands) More than 600 small, kidney bean-shaped lymph nodes are clustered throughout your body -- under your...
athe human skeleton has many bones.bones are hard on the outside,but they have soft bone marrow inside.bone marrow makes all the blood in the human body 正在翻译,请等待... [translate] awe should not throw the rubbish anywhere and draw on the wall 我们在墙壁上不应该投掷任何地方垃圾和画[...
Studies have shown that symptoms such as vision, hearing, hepatosplenomegaly, lung function, and a coarse face improve after HSCT, but this improvement is not obvious in bones, heart valves, or the damaged nervous system because of relatively few blood vessels and limited enzyme production by ...
athe human skeleton has many bones.bones are hard on the outside,but they have soft bone marrow inside.bone marrow makes all the blood in the human body 正在翻译,请等待... [translate] aKooperationsunabhängig 正在翻译,请等待...
athe human skeleton has many bones.bones are hard on the outside,but they have soft bone marrow inside.bone marrow makes all the blood in the human body 正在翻译,请等待... [translate] a在我小的时候 Is small in me[translate] ashe just gone from one .. to the other 从一个去的她。
athe human skeleton has many bones.bones are hard on the outside,but they have soft bone marrow inside.bone marrow makes all the blood in the human body 正在翻译,请等待... [translate] a影响我职业选择的因素首先是兴趣,其次是自己的追求和曾经的梦想。 Affects my occupation choice the factor fi...