A Level Biology Practice Exam 2025 – All-in-One Study Guide to Excel in Your A Levels!

Goblet cells are specialized epithelial cells primarily responsible for the secretion of mucus. This mucus plays a critical role in protecting and lubricating the surfaces of various tissues in the body, such as the respiratory and gastrointestinal tracts. By producing mucus, goblet cells help trap pathogens, dust, and other particles, facilitating their removal from the body and preventing infection. Additionally, the mucus serves to maintain moisture in the epithelial cells, enhancing their functionality and overall health. This protective function is vital for maintaining the integrity of the lining of various organs and systems.

The other options highlight activities that are associated with different cell types within the body. For instance, enzymes for digestion are primarily secreted by cells in the pancreas and the stomach lining, while nutrient absorption is carried out by enterocytes in the intestinal tract. Oxygen transport in the blood is a function of red blood cells, specifically through the protein hemoglobin. Thus, the unique role of goblet cells in mucus secretion stands out distinctly in the context of overall bodily functions.