The nucleus is an organelle found in eukaryotic cells. Inside its fully enclosed nuclear membrane, it contains the majority of the cell's genetic material. This material is organized as DNA molecules, along with a variety of proteins, to form chromosomes.
First, a complete digestive system means that the digestive tract has a beginning or the oral end and the opposite end or the aboral end. This is found in more complex animals starting from roundworms (flatworms have an incomplete digestive tract). A closed circulatory system is found in animals more recent than mollusks. The presence of the coelom makes it more evolved than the flatworms.
Specifically, a small animal with a segmented body, short stiff appendages, and soft skin with the above characteristics point out to the phylum Annelida or annelids.
The organelle that is most likely malfunctioning in the patient's cells would be B. Lysosomes.
