The density of an object determines whether it will float or sink in another substance. An object will float if it is less dense than the liquid it is placed in. An object will sink if it is more dense than the liquid it is placed in.
So an object denser than water will sink
Answer: C. scorpions have changed as a result of natural selection
Explanation:
The text tells us that scorpions today are now smaller than they were in the past. This means that the scorpions have changed since then i.e. they have evolved.
The primary reason for evolution is natural selection which refers to a situation whereby only the organisms that are better adapted in their species survive.
The conclusion that can be drawn from this research therefore is that we have smaller scorpions today because they stood a better chance of survival than the larger ones and so survived whilst the larger ones died out.
It would be rainforests because it obviously gets a lot of rain and the rain makes the humidity high.