Answer:
mutation in DNA
Explanation:
Mutations are changes in the genetic code that can occur in many ways. Each time a cell divides, say, DNA must be copied into two copies, one copy for each new cell. Although this copying is very precise, it is still not perfect - for about every billion accurately copied databases, one is mistranslated.
Another source is DNA damage, which can occur spontaneously through the normal life of the cell, or through external toxins or negative influences (ultraviolet radiation, for example). Through evolution, cells have developed a very complex system for repairing changes in DNA, but these systems not only have limitations but can sometimes cause additional errors themselves.
<span>Similarities and differences between intramembranous and endochondral ossification<span>
Ossification is the process of bone formation. Intramembranous and endochondral ossification are the two main processes of bone formation that occur during fetal development.
</span>Similarities between intramembranous and endochondral ossification<span>; they turn cartilage into bones during bone formation and they both involve bone cells such as calcium, vascular supply and osteoblasts.
</span>Differences between intramembranous and endochondral ossification<span>; In intramembranous ossification, an intermediate cartilage is not involved, rather the bone tissue is directly laid on a primitive connective tissue called mesenchyma while in endochondral ossification, cartilage is used as a precursor for bone formation. Also, in cases of fractures, the healing process by plaster of Paris occurs through endochondral ossification while fractures which are treated by open reduction and internal fixation are healed by intramembranous ossification.
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"<span>Covered with an enormous sheet of ice" would most likely match Europe, although it should be noted that this was a while ago and changes with time. </span>
The diaphragm is the large flat muscle. hope that helps :)