<span>A scientific theory summarizes a hypothesis or group of hypotheses that have been supported with repeated testing.A scientific theory is a well-substantiated
explanation of some aspect of the natural world, based on a body of
facts that have been repeatedly confirmed through observation and
experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world.</span>
The given statement is False.
Africa was not covered with glaciers during the Pleistocene ice age. Africa was divided into different parts and some part of Africa was was greener and full of different kinds of species.
The tropical Africa had 5 degree less than the temperature of the Africa right now. There were different plant and animals species present at that time.
They could improve the experiment that they made by adding another variable such as: watering the plants with fresh water. This way they could have a better comparison how plants grow based on the type of water they are exposed with.