Consider the following research question.
 Research Question: Why is yeast used to bake bread?
 Which hypothesis is based on this research question?
 A. Yeast is a living organism.
 B. Some people try to lose weight by cutting bread out of their diet.
 C. A comparison of rye bread to wheat bread indicates that rye bread
 is more enjoyable to eat.
 O D. Yeast added to bread dough produces a gas, and this causes the
 dough to rise, making the finished bread look like a sponge.