Given a scientific passage and an answer, generate a question for the given answer.

Q: Passage: One useful application of PET scanning is in the diagnosis of Alzheimer's disease. This debilitating condition associated with memory loss primarily occurs in elderly individuals. A protein known as beta-amyloid gradually forms deposits, or plaques, in the brain. Severe memory loss and impaired movement appear to be direct results of the plaque growth. Answer: elderly

A: Alzheimers disease is associated with memory loss in what group of people?
****
Q: Passage: 41.4 Nitrogenous Wastes Ammonia is the waste produced by metabolism of nitrogen-containing compounds like proteins and nucleic acids. While aquatic animals can easily excrete ammonia into their watery surroundings, terrestrial animals have evolved special mechanisms to eliminate the toxic ammonia from their systems. Urea is the major byproduct of ammonia metabolism in vertebrate animals. Uric acid is the major byproduct of ammonia metabolism in birds, terrestrial arthropods, and reptiles. Answer: urea

A: When vertebrate animals metabolize ammonia what is the primary byproduct that is produced?
****
Q: Passage: To ensure that no more than one sperm fertilizes the egg, once the acrosomal reactions take place at one location of the egg membrane, the egg releases proteins in other locations to prevent other sperm from fusing with the egg. If this mechanism fails, multiple sperm can fuse with the egg, resulting in polyspermy. The resulting embryo is not genetically viable and dies within a few days. Answer: polyspermy

A:
What is the term for if multiple sperm fuse with an egg?
****