Your answers are both evocative and active forces. Hope this helps.
Because they don't need them. Cell walls, which are found in plant cells, maintain cell shape, almost as if each cell has its own exoskeleton. This rigidity allows plants to stand upright without the need for bones .
<span>The elements found in abundance in living organisms are elements such as : carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur.</span>
