Answer:Biological structures are able to adapt their growth to external mechanical stimuli and impacts. For example, when plants are under external loads, such as wind force and self-weight, the overloaded zones are reinforced by local growth acceleration and the unloaded zones stop growing or even shrink. Such phenomena are recorded in the annual rings of trees. Through his observation of the stems of spruce, K. Metzger, a German forester and author, realized that the final goal of the adaptive growth exhibited by biological structures over time is to achieve uniform stress distribution within them. He published his discovery in 1893.12 A team of scientists at Karlsruhe Research Centre adopted Metzger's observations and developed them to one single design rule: the axiom of uniform stress. The methods derived from this rule are simple and brutally successful like nature itself. An excellent account of the uniform-stress axiom and the optimization methods derived from it is given by Claus Mattheck in his book ‘Design in Nature’.13 The present study utilizes one of these methods, stress-induced material transformation (SMT), to optimize the cavity shape of dental restorations.
Explanation:
Answer:
Hard
Explanation:
it is hard because these are usually hard parts of an organism including shells, bones, teeth, woody trunk, stems, and branches.
Answer:
B. Populations of amphibians in a few local areas have declined dramatically in the last few decades
Explanation:
The continuous, low-level extinction of species that has occurred throughout the World and at least six species of frogs have not been seen for one to three decades and also it has recently been discovered that some species of salamander-specific chytrid has gone into extinction
