The answer is #4. The first and second one involve acid, which is chemical weathering. The third one involves oxidation, which is a chemical process. The only mechanical process is option four.
The correct answer is: 2- Hypertension, or high blood pressure
Hypertension leads to heart failure. Also, as a result of hypertension body tends to retain fluid in order to maintain adequate blood volume. A failing heart is unable to handle that extra fluid, so it is transferred out of the blood vessels and into tissues causing the swelling of extremitets or edema.
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.
The answer to the question is option C
The epiglottis. It prevents food from entering the respiratory tract