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).
If a group of people are sharing costs for a qualifying relative, a multiple support declaration (IRS Form 2120) can be filed to grant one family member the exemption. This is subject to certain conditions, says Ron Nagle, CPA, senior tax manager of Clothier & Head in Seattle.