Answer:
The fourth plant that receives pure water is the control group.
Explanation:
The election of a control group is essential in an experiment. Its principal purpose is to allow the discrimination of the results obtained by the treatment in the study, in this case, <em>the different concentrations of salty water that each plant receives</em>. The control group provides a reference point. It must be selected from the same population of the treatment groups. Both groups must be similar in every variable that might influence the results, <u>except for the study treatment.</u>
Answer:
B. Earth rotates on its own axis and revolves around the Sun.
Explanation:
The earth moves not only in one way but in two ways. It revolves around its axis and revolves around the Sun.
We do not notice it because we are on Earth and we turn together with it.
When the Earth revolves around its (imagined) axis, we call such a movement a rotation, and when it revolves around the Sun - a revolution.
