The separation of sister chromatids occurs during anaphase. At this stage, the cohesin proteins that hold the sister chromatids together are cleaved, allowing the chromatids to part ways. Kinetochore microtubules attached to the chromatids shorten, pulling each chromatid toward opposite poles, while nonkinetochore microtubules push the poles further apart. This movement ensures that each new daughter cell will receive an identical set of chromosomes. Before this, chromosomes condense in prophase and align at the center of the cell in metaphase; afterward, in telophase, the chromosomes arrive at the poles and the nuclear envelope begins to reform.

A fungus infection of the skin is described as dermatomycosis. The term combines dermato-, meaning skin, with mycosis, meaning a fungal infection, to specify a fungal involvement of the skin. This is why it’s the best choice: it directly denotes a fungal skin infection. Dermatitis means inflammation of the skin and can have many causes; a dermatologist is the doctor who specializes in skin conditions; diuresis is increased urine production, not related to skin infections. For reference, specific fungal skin infections are often categorized under dermatomycoses, with common examples including tinea infections like ringworm.

Recording pictures of a joint involves imaging to visualize its internal structures. The term combines arthro- meaning joint with -graphy meaning recording or imaging. In arthrography, contrast dye is often injected into the joint to outline the joint space, ligaments, and cartilage so that X-ray, CT, or MRI can clearly show abnormalities. This is different from other procedures: drawing fluid from a joint is arthrocentesis, surgically fusing a joint is arthrodesis, and replacing a joint is arthroplasty. Therefore, the term for recording pictures of a joint is arthrography.

The main idea is recognizing how medical terms are built to name conditions. The term for having gallstones is cholelithiasis. It combines chole- (bile), lith- (stone), and -iasis (a condition or presence). So it literally means a condition of stones in the bile system, which is exactly what “gallstones” describes. This is why it’s the right choice: it names the stone condition itself in the gallbladder or biliary tract. The other terms refer to different things—cholecystectomy is a surgical procedure to remove the gallbladder, cholecystitis is inflammation of the gallbladder (often due to stones but not the stone condition itself), and chondromalacia is a cartilage-softening issue elsewhere in the body, not related to the biliary system.