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.
I'm pretty sure its c or d
<span>When plants moved on the land they had to adapt to new environment and </span>to deal with new <span>problems. The main problem for plants was to figure out how to regulate water loss within the cells. One of the solution was the formation of the waxy covering on top of leaves-cuticle, which evolved on the surface of leaves to reduce water loss. Another problem for plants was to figure out how to obtain resources from soil and air, so they developed vascular tissue to transport water/sugar within the plant.</span>
Plants and animals provide food for humans. Plants cycle the air for humans too.
D: Human feet come in a wide range of sizes. There isn't a lot of gray area or space for ranges of things in medel's laws, but they still work in a lot of cases.