<span>The principal components of the plasma membrane are lipids (phospholipids and cholesterol), proteins, and carbohydrate groups that are attached to some of the lipidsand proteins. A phospholipid is a lipid made of glycerol, two fatty acid tails, and aphosphate-linked head group.
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Chloroplast , cell walls and centriols can be found in plant cell but not in animal cells.
The pit that marks the location of the umbilical cord after birth is known as the navel or belly button. All animals that grow placenta during fetal development will have a navel or belly button. The scientific name of the structure is the umbillicus. It can be a depression in some individuals or raised in others.
Cell -> tissue -> organ -> organ system -> organism
