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

[Q]: Passage: Heat waves have increased in frequency and duration in recent years. The summer 2011 North American heat wave brought record temperatures across the Midwestern and Eastern United States. Many states and localities broke records for temperature and for the most days above 100 o F. Answer: cell membrane
[A]: What are all cells surrounded by?

[Q]: Passage: According to the cell theory , all living things are made up of cells, which is the structural unit of living organisms, and living cells always come from other living cells. In fact, each living thing begins life as a single cell. Some living things, such as bacteria, remain single-celled. Other living things, including plants and animals, grow and develop into many cells. Your own body is made up of an amazing 100 trillion cells! But even youlike all other living thingsbegan life as a single cell. Answer: trillions of cells
[A]: What is your body made up of?

[Q]: Passage: With less ozone in the stratosphere, more UV rays reach the ground. More UV rays increase skin cancer rates. Just a 1 percent loss of ozone causes a 5 percent increase in skin cancer. More UV rays also harm plants and phytoplankton. As a result, they produce less food. This may affect entire ecosystems. Answer: ozone
[A]:
More uv rays reach the ground due to a decrease in what layer in the stratosphere?