TASK DEFINITION: Given a scientific passage and an answer, generate a question for the given answer.
PROBLEM: Passage: Whales and bats have the trait of echolocation. This is the ability to locate objects in the dark by bouncing sound waves off them. The most recent common ancestor of whales and bats did not have this trait. Apply lesson concepts to explain how the trait evolved in whales and bats. Answer: echolocation

SOLUTION: What term is defined as the ability to locate objects in the dark by bouncing sound waves off them.

PROBLEM: Passage: Electromagnetic waves vary in their wavelengths, frequencies, and energy levels. The full range of electromagnetic waves makes up the electromagnetic spectrum. Answer: electromagnetic spectrum

SOLUTION: What do we call the full range of electromagnetic waves?

PROBLEM: Passage: The disintegration of unstable nuclei does not occur all at once. The rate of disintegration is a statistical process. The most convenient way to consider it is by a concept known as half-life . The time required for half of the atoms in any given quantity of a radioactive substance to decay is the half-life of that element. Each particular isotope has its own half-life. For example, the half-life of radium-226 is 1600 years. That is, beginning with 1.00 gram of radium-226, it would take 1600 years for half of it to decay and leave 0.50 gram remaining. After another 1600 years, only 0.25 gram would remain. In each half-life, exactly half of the beginning amount decays. Answer: half-life

SOLUTION:
What is the time it takes for radioactive substance to decay?