TASK DEFINITION: Given a scientific passage and an answer, generate a question for the given answer.
PROBLEM: Passage: Coal is the source of most electricity. Answer: coal

SOLUTION: What is the source of most electricity?

PROBLEM: Passage: Pea plants are naturally self-pollinating. In self-pollination , pollen grains from anthers on one plant are transferred to stigmas of flowers on the same plant. Mendel was interested in the offspring of two different parent plants, so he had to prevent self-pollination. He removed the anthers from the flowers of some of the plants in his experiments. Then he pollinated them by hand with pollen from other parent plants of his choice. When pollen from one plant fertilizes another plant of the same species, it is called cross-pollination . The offspring that result from such a cross are called hybrids. Answer: cross-pollination

SOLUTION: What is it called when pollen from one plant fertilizes another plant of the same species?

PROBLEM: Passage: Puberty is the stage of life when a child becomes sexually mature. Puberty begins when the pituitary gland tells the testes to secrete testosterone in boys, and in girls the pituitary gland signals the ovaries to secrete estrogen. Changes that occur during puberty are discussed in the Male Reproductive Development and Female Reproductive Development concepts. Answer: puberty

SOLUTION:
What is the name of the stage of life when a child becomes sexually mature?