Read the following passage and mark the letter A, B, C, or D on your answer sheet to choose the word or phrase that best fits each of the numbered blanks.

Water is indeed essential for all life on, in, and above the Earth. This is important to you because you are made up (46) _________ of water. Think of what you need to survive, really just survive. Food? Water? Air? Facebook? Naturally, everyone would concentrate on water here. Water is of major importance to all living things in some (47) ______________ up to 90% of their body weight comes from water. Up to 60% of the human adult body is water.

(48) _____________ Mitchell and others (1945), the brain and heart are composed of 73% water, and the lungs are about 83% water. The skin (49) _______________ 64% water, muscles and kidneys are 79%, and even the bones are watery: 31%.

Each day humans must consume a certain amount of water to survive. Of course, this varies according to age and gender and also by (50) _____________ someone lives. Generally, an adult male needs about 3 liters (3.2 quarts) per day while an adult female needs about 2.2 liters (2.3 quarts) per day. All of thewater a person needs does not have to come from drinking liquids, as some of this water is contained in the food we eat.