1 Intracellular fluid (2/3 of body water). 2  Per Guyton, in a body containing 40 litres of fluid, about 25 litres is intracellular, which amounts to 62.5% (5/8), close enough to the 2/3 rule of thumb. 3  Jackson's texts states 70% of body fluid is intracellular. 4  Extracellular fluid (1/3 of body water).
However, if you provided support to your brother, depending on the level of support and your brotherâs gross income for 2010, you may be able to claim him as a dependent on your tax return (under the qualifying relative rules).
Support Test. To claim your grandchildren, they cannot provide more than half of their own support. Support include costs such as housing, medical expenses, food, education and clothing. For example, if your grandchild provides 10 percent of his own support, his parents provide 45 percent and you provide 45 percent, you meet the support test. However, if the grandchild provides 51 percent of her own support and you provide 49 percent, you can't claim her.