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

Ex Input:
Passage: Air movement takes place in the troposphere. This is the lowest layer of the atmosphere. Air moves because of differences in heating. These differences create convection currents and winds ( Figure below ). Answer: troposphere

Ex Output:
What is the lowest layer of the atmosphere called?

Ex Input:
Passage: An addition reaction is a reaction in which an atom or molecule is added to an unsaturated molecule, making a single product . An addition reaction can be thought of as adding a molecule across the double or triple bond of an alkene or alkyne. Addition reactions are useful ways to introduce a new functional group into an organic molecule. Answer: an addition reaction

Ex Output:
What is a reaction in which an atom or molecule is added to an unsaturated molecule, making a single product?

Ex Input:
Passage: A desmosome is a cell junction specialized for cell-to-cell adhesion. They are found in simple and stratified squamous epithelium, and in muscle tissue where they bind muscle cells to one another. These junctions are composed of complexes of cell surface adhesion proteins and linking proteins. These proteins have both an intracellular and extracellular region. Inside the cell, they attach to intracellular filaments of the cytoskeleton. Outside the cell, they attach to other adhesion proteins. Answer: epithelium

Ex Output:
Where are the desmosome found in a cell?