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

Passage: The three types of muscles in the body include skeletal muscle, smooth muscle, and cardiac muscle. Answer: muscle
Smooth, cardiac, and skeletal are all types of what?

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
When vertebrate animals metabolize ammonia what is the primary byproduct that is produced?

Passage: Eukaryotic cells also contain other organelles besides the nucleus. An organelle is a structure within the cytoplasm that performs a specific job in the cell. Organelles called mitochondria, for example, provide energy to the cell, and organelles called vacuoles store substances in the cell. Organelles allow eukaryotic cells to carry out more functions than prokaryotic cells can. This allows eukaryotic cells to have greater cell specificity than prokaryotic cells. Ribosomes, the organelle where proteins are made, are the only organelles in prokaryotic cells. Answer: organelle
What is the term for a structure within the cytoplasm that performs a specific job in the cell?