Hi there!
The answer is C. nicotine.
Tobacco is the carrier of nicotine. This stimulates the brain but also makes you dependent, which can eventually cause (life-long) addiction.
The body fat percentage of a person or animal is the total weight of fat divided by total weight; body fat includes essential body fat and storage body fat. Essential body fat is necessary to maintain life and reproductive functions. [ The percentage of essential body fat for women is greater than that for men, due to the demands of childbearing and other hormonal functions. The<span> percentage of essential fat is 2 - 5% in men, and 10 - 13% in women.[1] Storage body fat consists of fat accumulation in adipose tissue, part of which protects internal organs in the chest and abdomen. The minimum recommended total body fat percentage exceeds the essential fat percentage value reported above. A number of methods are available for determining body fat percentage, such as measurement with calipers or through the use of bioelectrical impedance analysis. The body fat percentage is a measure of fitness level, since it is the only body measurement which directly calculates a person's relative body composition without regard to height or weight. The widely used body mass index (BMI) provides a measure that allows the comparison of the adiposity of individuals of different heights and weights. While BMI largely increases as adiposity increases, due to differences in body composition, it is not an accurate indicator of body fat; for example, individuals with greater muscle mass will have higher BMIs. The thresholds between "normal" and "overweight" and between "overweight" and "obese" are sometimes disputed for this reason
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A doctor that specializes in the treatment of tumors and cancer would be an oncologist.
Hope that helps!
