TASK DEFINITION: Given a scientific passage and an answer, generate a question for the given answer.
PROBLEM: Passage: Figure 43.17 Rising and falling hormone levels result in progression of the ovarian and menstrual cycles. (credit: modification of work by Mikael Haggstrom). Answer: hormones

SOLUTION: Rising and falling levels of what will result in progression of the ovarian and menstrual cycles?

PROBLEM: Passage: Radioactivity is the ability of an atom to emit, or give off, charged particles and energy from the nucleus. The charged particles and energy are called by the general term radiation . Only unstable nuclei emit radiation. When they do, they gain or lose protons. Then the atoms become different elements. (Be careful not to confuse this radiation with electromagnetic radiation, which has to do with the light given off by atoms as they absorb and then emit energy. ). Answer: radioactivity

SOLUTION: What is the ability of an atom to emit, or give off, charged particles and energy from the nucleus?

PROBLEM: Passage: Bombarding a target of one element with high-energy nuclei or subatomic particles can create new elements. Electrostatic repulsions normally prevent a positively charged particle from colliding and reacting with a positively charged nucleus. If the positively charged particle is moving at a very high speed, however, its kinetic energy may be great enough to overcome the electrostatic repulsions, and it may collide with the target nucleus. Such collisions can result in a nuclear transmutation reaction. Answer: electrostatic repulsions

SOLUTION:
What normally prevent a positively charged particle from colliding and reacting with a positively charged nucleus, but may be overcome by kinetic energy?.