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

Example Input: Passage: Some molecules, such as proteins, are too large to pass through the plasma membrane, regardless of their concentration inside and outside the cell. Very large molecules cross the plasma membrane with a different sort of help, called vesicle transport . Vesicle transport requires energy, so it is also a form of active transport. There are two types of vesicle transport: endocytosis and exocytosis. Both types are shown in Figure below and described below. Answer: active transport
Example Output: What type of transport is vesicle transport considered to be?

Example Input: Passage: - For lenses, the distance from the center of the lens to the focus is . Focal lengths are positive for converging lens and negative for diverging lens. The distance from the center of the lens to the object in question is , where distances to the left of the lens are positive in sign. The distance from the center of the lens to the image is . This number is positive for real images (formed to the right of the lens), and negative for virtual images (formed to the left of the lens). Answer: focal lengths
Example Output: What lengths are positive for converging lens and negative for diverging lens?

Example Input: Passage: Each protein has its own unique sequence and shape held together by chemical interactions. If the protein is subject to changes in temperature, pH, or exposure to chemicals, the protein structure may change, losing its shape in what is known as denaturation as discussed earlier. Denaturation is often reversible because the primary structure is preserved if the denaturing agent is removed, allowing the protein to resume its function. Sometimes denaturation is irreversible, leading to a loss of function. One example of protein denaturation can be seen when an egg is fried or boiled. The albumin protein in the liquid egg white is denatured when placed in a hot pan, changing from a clear substance to an opaque white substance. Not all proteins are denatured at high temperatures; for instance, bacteria that survive in hot springs have proteins that are adapted to function at those temperatures. Answer: denaturation
Example Output:
Each protein has its own unique sequence and shape held together by chemical interactions. if the protein is subject to changes in temperature, ph, or exposure to chemicals, the protein structure may change, losing its shape in what is known as this?