The primary characteristics of cystic fibrosis include ____.

A) sickling of red blood cells and pain in the extremities
B) defective connective tissues
C) development of malignant cells
D) buildup of mucus in the passageways and ducts throughout the body
E) extreme fever and diarrhea

Cystic fibrosis is a genetic disorder that causes thick, sticky mucus to build up in the lungs, pancreas, and other organs. This buildup of mucus can block airways, leading to lung infections, and also affect the digestive system, causing problems with digestion and nutrient absorption. Symptoms can include difficulty breathing, chronic cough, poor growth and weight gain, and salty-tasting skin. Sickling of red blood cells and pain in the extremities are associated with sickle cell anemia, a different genetic disorder. Defective connective tissues can indicate a range of connective tissue disorders, such as Ehlers-Danlos syndrome. Development of malignant cells refers to the growth of cancerous cells, which is not a characteristic of cystic fibrosis. Extreme fever and diarrhea can indicate an infection or gastrointestinal disorder, but are not specific to cystic fibrosis.