Red blood cells are not considered fully mature until they have lost their nucleus, ribosomes, and mitochondria. This may seem strange, and it is very odd for a cell not to have a nucleus, ribosomes, or mitochondria, but in the case of red blood cells, they don't really need them.fter all, red blood cells have to come from somewhere, and cells do need mitochondria and a nucleus with DNA to go through mitosis, make new cells, and make all of that hemoglobin protein. As it turns out, immature red blood cells do have mitochondria and a nucleus for just those reasons.
Definition of a Trapezoid. A trapezoid is a 2-dimensional geometric figure with four sides, at least one set of which are parallel. The parallel sides are called the bases, while the other sides are called the legs.
A trapezoid is defined as a four-sided polygon with one pair of parallel sides. A rectangle is a four-sided polygon with each side parallel to its opposite side (basically, two pairs of parallel sides) and four right angles, so all rectangles could technically be considered as trapezoids. Hope this helps.