As the yeast feeds on the sugar, it produces carbon dioxide. With no place to go but up, this gas slowly fills the balloon.
A very similar process happens as bread rises. Carbon dioxide from yeast fills thousands of balloonlike bubbles in the dough. Once the bread has baked, this is what gives the loaf its airy texture.
Statement 3 does. Hope that helps :)
The statement that would discredit Pott's objectivity if it was included in the article is I believe the human race is capable of great things.
That statement gives shows his opinion, making it subjective.
The article Rick Potts wrote in 1998 is a credible source of information because it is objective, reviewed by other scientists and written by the director of the Smithsonian's Human Origin Program.
Answer:
The immune, lymphatic, and circulatory systems work together in protecting the body.