question: How can our skeleton achieve being EXTREMELY light and also capable of supporting EXTREMELY heavy weights at the same time?
comment: Humans don't intuitively have a good grasp for forces and stresses when they are outside the range of simple objects we can pick up. Bone seem's impressive when we compare with what we can break and pick up with our own muscular skeletal system. But that's because our strength and intuition is already limited by bone. Functionally, bone has fairly good strength to weight due to it having a high 'second moment of area' i.e. there is more material around the edges and less in the middle. It also has the advantage of changing its internal structure to become stronger in certain directions after repeated use. However as an engineering material, bone isn't actually that impressive, compared with the vast catalogue of materials at our disposal. It's not the strongest, and it's quite brittle. If it were super impressive, we'd be sure to find plenty of structural applications for it right away.
passages: An external skeleton can be quite heavy in relation to the overall mass of an animal, so on land, organisms that have an exoskeleton are mostly relatively small. Somewhat larger aquatic animals can support an exoskeleton because weight is less of a consideration underwater. The southern giant clam, a species of extremely large saltwater clam in the Pacific Ocean, has a shell that is massive in both size and weight. "Syrinx aruanus" is a species of sea snail with a very large shell.
  
  Section::::Types of skeletons.:Endoskeleton.
   Another function of bones is the storage of certain minerals. Calcium and phosphorus are among the main minerals being stored. The importance of this storage "device" helps to regulate mineral balance in the bloodstream. When the fluctuation of minerals is high, these minerals are stored in bone; when it is low it will be withdrawn from the bone.
  
  Section::::The different muscles.:Muscular.
   Galileo Galilei was interested in the strength of bones and suggested that bones are hollow because this affords maximum strength with minimum weight. He noted that animals' bone masses increased disproportionately to their size. Consequently, bones must also increase disproportionately in girth rather than mere size. This is because the bending strength of a tubular structure (such as a bone) is much more efficient relative to its weight. Mason suggests that this insight was one of the first grasps of the principles of biological optimization.
   Similar to traits on a genetic level, aspects of organs can also be subject to co-adaptation. For example, slender bones can have similar performance in regards to bearing daily loads as thicker bones, due to slender bones having more mineralized tissue. This means that slenderness and the level of mineralization have probably been co-adapted. However, due to being harder than thick bones, slender bones are generally less pliant and more prone to breakage, especially when subjected to more extreme load conditions.
   Section::::Description.:Skeleton.
   Section::::Organisms with skeletons.:Vertebrates.:Birds.
  
  The bird skeleton is highly adapted for flight. It is extremely lightweight, yet still strong enough to withstand the stresses of taking off, flying, and landing. One key adaptation is the fusing of bones into single ossifications, such as the pygostyle. Because of this, birds usually have a smaller number of bones than other terrestrial vertebrates. Birds also lack teeth or even a true jaw, instead having evolved a beak, which is far more lightweight. The beaks of many baby birds have a projection called an egg tooth, which facilitates their exit from the amniotic egg.
   strength, and it must be acknowledged the charge is not altogether without foundation. But, for my part, I no more regret the want of that vigour which I possessed in my youth, than I lamented in my youth that I was not endowed with the force of a bull or an elephant. It is sufficient if we exert with spirit, upon every proper occasion, that degree of strength which still remains with us.” The aging process remains an inevitable part of the life cycle, but science is now being used to treat the deterioration of the human body so that the aging population can live with independence and comfort.
   Section::::Lift.
   The joints between bones allow movement, some allowing a wider range of movement than others, e.g. the ball and socket joint allows a greater range of movement than the pivot joint at the neck. Movement is powered by skeletal muscles, which are attached to the skeleton at various sites on bones. Muscles, bones, and joints provide the principal mechanics for movement, all coordinated by the nervous system.
   Section::::Description.:Appendicular skeleton.
   Skeletal pneumaticity allows animals to redistribute the skeletal mass within their body. The skeletal mass of a bird (pneumatized) and a mammal (not pneumatized) with similar body size is roughly the same, yet the bones of birds were found to be denser than the bones of mammals. This suggests that pneumatization of bird bones does not affect the overall mass but allows for a better balance of weight within the body to allow for greater balance, agility and ease of flight.
  
  Section::::Function of skeletal pneumaticity.:Balance.
   Skeletal muscles produce reactive forces and moments at the joints. To avoid injury or fatigue, when person is performing a task, such as pushing or lifting a load, the external moments created at the joints due to the load at the hand and the weight of the body segments must be ideally less than the muscular moment strengths at the joint.
  
  One of the first sagittal-plane models to predict strength was developed by Chaffin in 1969. Based on this model, the external moments at each joint must not exceed the muscle strength moments at that joint.
  
  M  S
   Section::::Discovery and naming.
  
  Section::::Discovery and naming.:"Scrotum humanum".
   The result of the activity is a structure more suited for the type and magnitude of the load it is carrying. For example, an orientation change of a beam could reduce the maximum stress or strain level, while a shape change could render a structure less susceptible to dynamic vibrations. A good example of an adaptive structure is the human body where the skeleton carries a wide range of loads and the muscles change its configuration to do so. Consider carrying a backpack. If the upper body did not adjust the centre of mass of the whole system slightly by leaning forward, the person would fall on his or her back.
   The employment of isometric presses in order to aid explosive power movements is also found in sports such as boxing. Here, the boxer may bend their lead leg, while positioning their torso and its respective bodyweight over it, so there exists equal forces between the upwards force of the bent leg and the downward force of the torso. The boxer then throws a lead hook from this position and the forces from the isometric press are channelled into the punch and help to increase its overall power. Such a channelling of force fundamentally represents the purpose of an isometric preload: which is as a preparatory action to aid a subsequent power movement.
   BULLET::::- MPCM-LH-26189 a/b: A partial skeleton of a hatchling from Las Hoyas in Spain, including both slab and counter-slab components. Its 2018 description revealed how various features developed in enantiornitheans as they aged. Such features include the ossification of the sternum from various smaller bones, and the fusion of tail vertebrae into a pygostyle.
   Only Count Dracula and his predecessor Varnae being known to lift more at 14 and 17 tons respectively due to their advanced age and special stance as ruler of Earth's vampire race.
  
  Section::::Characteristics.:Willpower.
   Section::::Description.:Hip.
   MyoD is one of the earliest markers of myogenic commitment. MyoD is expressed at extremely low and essentially undetectable levels in quiescent satellite cells, but expression of MyoD is activated in response to exercise or muscle tissue damage. The effect of MyoD on satellite cells is dose-dependent; high MyoD expression represses cell renewal, promotes terminal differentiation and can induce apoptosis. Although MyoD marks myoblast commitment, muscle development is not dramatically ablated in mouse mutants lacking the MyoD gene. This is likely due to functional redundancy from Myf5 and/or Mrf4. Nevertheless, the combination of MyoD and Myf5 is vital to the success of myogenesis.
   The basis of osteogenic loading stems from Wolff's law, which shows that the force or loading on bone through its axis, can stimulate the bone's natural function of increasing in density. Further study has shown that greater loads on bone can stimulate a greater effect of the body to respond and increase the density of bone, and can show immediate effects in the body via blood testing showing bone turnover markers This high level of loading on bone would typically be seen in high-impact activity, which is not practical for therapy given the risk of injury potential.
   The structure of the skin of the patagia and accessory areas for the patagia of a Ptychozoon kuhli, flying gecko, exhibiting the passive gliding mechanism consists of five layers; a layer of adipose tissue is surrounded by a layer of dermis on each side (ventral and dorsal) and a layer of epidermis is external to the two dermal layers. The distribution of the adipose tissue IS thickest close to the body wall. This thick layer of adipose tissue at close to the body wall is believed to provide a "safety factor" for the structural elements of the skin ( i.e. collagen fibers) near the body wall. The thick layer of adipose tissue is more compliant than the structural elements of the body wall (i.e. ribs, muscles), therefore will more readily deform(absorb force) before the structural elements of the skin experience a force. The layer of adipose tissue also aids in the creation of the domed and cambered shape of the patagia. With regards to the structure of the dermal layer of the patagia, there is a thick layer of collagen fibers oriented parallel to the axis of the patagial ribs. These collagen fibers act as the structural support for the shape of the patagia, and provide the stiffness necessary to resist shape chang . The most prominent features of the epidermal layer of the patagia are the scales. The morphology of the dorsal scales of the patagia change as a result of their functional role. A large portion of the dorsal scales of the patagia are arranged in regular rib-like pattern, which guide the flow of air and allow for the lizard to behave as an airfoil. However at the hinge joints (places where patagia folds and attaches to limbs), the regular rib like structure of scales breakdown into a more random distribution of scales. This breakdown of scales is believed to aid in the mechanical loading of the patagia during the unfurling process and also determining the extent the patagia unfurling during flight.
   An alternative approach is to consider the pelvis part of an integrated mechanical system based on the tensegrity icosahedron as an infinite element. Such a system is able to withstand omnidirectional forces—ranging from weight-bearing to childbearing—and, as a low energy requiring system, is favoured by natural selection.
   However, "Sauroposeidon" has a gracile neck compared to "Giraffatitan". If the rest of the body turns out to be similarly slender, the mass estimate may be too high. This could be similar to the way the relatively robust "Apatosaurus" weighs far more than the longer but much slimmer "Diplodocus". In addition, it is possible that sauropods may have had an air sac system, like those in birds, which could reduce all sauropod mass estimates by 20% or more.
  
  Section::::Palaeoecology.
   The structure elements are combined in "structural systems". The majority of everyday load-bearing structures are "section-active" structures like frames, which are primarily composed of one-dimensional (bending) structures. Other types are "Vector-active" structures such as trusses, "surface-active" structures such as shells and folded plates, "form-active" structures such as cable or membrane structures, and hybrid structures.
  
  Load-bearing biological structures such as bones, teeth, shells, and tendons derive their strength from a multilevel hierarchy of structures employing biominerals and proteins, at the bottom of which are collagen fibrils.
  
  Section::::Biological.
   The pectoral and pelvic girdles are notably distinct. The forelimbs are smaller and more gracile than the hindlimbs, suggesting that the center of mass for "Tanystropheus" was closer towards the pelvic girdle. Attachment sites for the "m. caudofemoralis" muscle complex, coupled with soft-tissue preservation of relative muscle size, further support the proposition that "Tanystropheus" was a fairly bottom-heavy animal.
  
  Section::::Paleoecology.
  
  Section::::Paleoecology.:Diet.
  
presuppositions: Bones are capable of supporting extremely heavy weight.  Bones are very impressive and capable of many things. 
corrections: Bones are not as capable of supporting extremely heavy weights outside of the body, but humans perceive bone as being impressive.  While bones are capable of many things, they aren't as impressive as they seem. 
raw_presuppositions: Bones are capable of supporting extremely heavy weight.  Bones are very impressive and capable of many things.  Bones are very impressive and capable of many things. 
raw_corrections: Bones are not as capable of supporting extremely heavy weights outside of the body, but humans perceive bone as being impressive.  While bones are capable of many things, they aren't as impressive as they seem.  While bones are capable of many things, they aren't as impressive as they seem. 