Carlos investigates the effect of magnesium on plant growth.
Carlos makes a hypothesis about the effect of magnesium on plant growth.
He uses the equipment in the diagram.

In his first experiment Carlos:
• fills a beaker with a solution containing all the minerals needed for healthy growth
• assembles the equipment and seedling as shown in the diagram
• records the appearance of the seedling after four weeks.
Carlos repeats the experiment.
In his second experiment, he uses a solution that contains all the minerals needed for healthy
growth except magnesium.
(i) Carlos makes a hypothesis about the effect of magnesium on plant growth.
Suggest a suitable hypothesis.