Answer:
C and D
Step-by-step explanation:
In the first problem, we have an experiment where a stimulus is constantly being applied to see results. This experiment should be drawn using a line graph, because this type of graph will show the linear relation between the two variables, that is, the fertilizer and the plant growth. Through this graph, you would observe is the relation is directly proportional or inversely proportional.
So, the first answer is C. line graph.
In the second problem, the best hypothesis would be D. the addition of different substances affects the freezing point of water, because the experiment include 1 beaker with just water, and two other beakers with different substances in them, this means that the researcher wants to know if different substances changes the freezing point.
If the experiment have only salt or only water, the possible hypothesis would be around the change of the freezing point due to a specific substance, but that's not the case here.
Therefore, the answers are C and D.