instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
Producing sperm and secreting testosterone are the main functions of male reproductive system system.
answer:
Producing sperm and secreting testosterone are the main functions of what system?


question:
Hydrocarbons compounds, which serve as fuels and are used in manufacturing, are called the driving force of western civilization.
answer:
What compounds, which serve as fuels and are used in manufacturing, are called the driving force of western civilization?


question:
Ossification begins approximately six weeks after fertilization in an embryo.
answer:

What begins approximately six weeks after fertilization in an embryo?