Ms. Snyder's students were studying living things and energy. They emptied a package of yeast into a cup of warm water. Next they
added.5 grams of sugar. After 15 minutes, the students noticed bubbles forming on the surface of the water. Using a dropper, they
put a sample of the liquid on a glass slide and looked at the sample with a microscope. The yeast cells were growing and
reproducing. The bubbles were a by-product of the yeast using the sugar for energy. What were the bubbles made of?
A)
oxygen
B)
water
hydrogen
D)
carbon dioxide