These bones are expanded into broad, flat plates, as in the cranium (skull), the ilium (pelvis), sternum and the rib cage. The flat bones are: the occipital, parietal, frontal, nasal, lacrimal, vomer, hip bone (coxal bone), sternum, ribs, and scapulae. ... In an adult, most red blood cells are formed in flat bones.
It is called a sister chromatid, not a polar body.
One is through turgidity. this occurs before ground tissue ( collenchyma and sclerenchyma cells) become well developed to give structural support to the plant as it grows bigger. The xylem tissue (composed of rigid tissue) of the young plant render this support and also maintaining osmotic turgidity of the surrounding plant cells.
Plasmolysis is the reason. The reason that the Elodea cell prevents from collapsing completely is that the Plasmolysis is the main reason because it always has water to keep it full. The answer in this question is Plasmolysis is the reason because it always has water to keep it full.