61. Get identical plastic cups and put coffee in some and thick tomato soup in the other. Heat them both until they reach the same temperature. Then wait like 10 minutes. Measure the temperature, record the results. Repeat several times for reliability. Safety considerations: Don't touch the cups when they're hot >_>
you should obviously write this out like an experiment.
67. a) In any given species there is a variation in the characteristics of species. Those that have favourable characteristics that let them survive are able to reproduce. In the diagram, even though most of the bacteria were killed, those which survived are able to reproduce and thus create a population of bacteria immune to the thing, thus natural selection has occured.
b) Mutations alter the characteristics of a species. These changes can increase chances of survival. (eg. a green lizard might survive longer than say, a red one, if you were in a forest and there was something that hunted lizards :x)