Living things need water in their cells. Water is the universal solvent - most of the chemicals a cell needs is dissolved and transported in water. Water is an environment where chemical reactions can occur and water is needed in many of those reactions - like the hydrolysis reaction (needed in the break down of food molecules). If a cell becomes dehydrated chemical reactions slow down. Chemical balance of the cell is changed as waste materials are not removed fast enough, food is not broken down, etc. Water also helps regulate the heat that can build up in a cell during chemical reactions. A dehydrated cell = increase in cell temp. Water content of a cell also affects the pH of a cell environment. Certain reactions occur better at certain pH. Homeostasis is maintaining a balance with the the environment. Without water the balance is upset.
Probably the last one. It's the least realistic way to make your body healthy. If you are going to do exercise and make yourself healthy, friends would be helpful in that process and exercising is definitely a good way to be healthy.
D. The percentage of muscle and body fat is often defined as the mass of the body which is why this is taken into account when measuring the BMI for children and teens. It might not use all of the fat, but some parts of it is needed to measure the mass effectively.
Trepanation consisted on drilling a hole on a person's skull to relieve the pressure of blood after an injury and treat intercranial diseases. It is presumed this surgery exists from the Neolithic Age and has been done first by Egyptians, Greeks, Romans and Indians.
Tell her to wait until October to discuss plan choices with you so that you can share plan benefits for the current year as well as any changes for the following year that may impact her choice
