Evolution of new diseases I think is the answer you're looking for.
A substance floats if it is less dense, or has less mass per unit volume, than other components in a mixture. For example, if you toss a handful of rocks into a bucket of water, the rocks, which are dense compared to the water, will sink. The water, which is less dense than the rocks, will float. Basically, the rocks push the water out of the way or displace it. For an object to be able to float, it has to displace a weight of fluid equal to its own weight.
Water reaches its maximum density at 4 C (40 F). As it cools further and freezes into ice, it actually becomes less dense. On the other hand, most substances are most dense in their solid (frozen) state than in their liquid state. Water is different because of hydrogen bonding.
Answer:
Gas.
Explanation:
Gas which is present makes the three bottles different from one another. There are three factors which is used for testing of cellular respiration such as amount of oxygen consumed during this process, amount of glucose used and amount of carbondioxide produced during cellular respiration. During cellular respiration, oxygen used in order to break down glucose and releases high amount of energy with the waste materials such as carbondioxide gas.
