Water can dissolve salt because the positive part of water molecules attracts the negative chloride ions and the negative part of water molecules attracts the positive sodium ions. The amount of a substance that can dissolve in a liquid (at a particular temperature) is called the solubility of the substance. - Google
this is the answers and working out to both questions
Answer/Explanation:
Experimental investigations are the best type of scientific investigation to demonstrate cause-and-effect relationships because they allow the investigator to actively manipulate variables and control conditions. This change can be measured to gather evidence to support or refute the cause-and-effect relationship. Experimental investigations also use a control group a group that does not receive the factor being tested for comparison.