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.
Others define a trapezoid as a quadrilateral with at least one pair of parallel sides (the inclusive definition), making the parallelogram a special type of trapezoid. The latter definition is consistent with its uses in higher mathematics such as calculus.he parallel sides are called the bases of the trapezoid and the other two sides are called the legs or the lateral sides (if they are not parallel; otherwise there are two pairs of bases). A scalene trapezoid is a trapezoid with no sides of equal measure, in contrast to the special cases below.