<span>Some of the things that would make the experiment invalid would be, if there was a variation in the behavior of the class with respect to food - for example, if some people ate their breakfast earlier than the others. This then would mean that some students would have already digested their breakfast during the morning classes and the others would still be digesting. </span>
Fossil fuels and green house gases which burn holes in the ozone layer of the atmosphere causing global warming
<span>Fungi obtain nutrients by absorption</span>
I believe that the answer is: Most organisms are made up of one or more cells
Cell Theory was first developed in 1839 by Schleiden and Schwann, they stated that all organisms are composed of one or more cells.
