Choose the correct option.

The situation is as close to a scientific experiment as it ... possible to find in the field, that is, without direct and deliberate intervention. The American and the Mexican Pima ... essentially the same genotype, and until a few generations ago they also ... the same phenotype. In other words, although they ... very similar genetic make-up, the two groups, which once had the same body shape, now ... different and ... different health problems. This genotype-phenotype distinction is a fundamental one for any study of genetics.
Neel \(1962\) proposed that the predisposition towards diabetes ... by what he called a ‘thrifty gene', one that ... the body to store fat when food is plentiful, in preparation for the famine that ... around the corner. This theory has undergone modification in the past half-century. Barker's hypothesis \(1997\) posits a 'thrifty phenotype': if a pregnant woman is starved of nutrients, her baby ... born small, and is likely to develop certain diseases later in life. The growing foetus is prepared for a life in which famine ... likely. In reality, of course, famine ... increasingly unlikely for most citizens in most countries today. We suffer from the opposite problem, overnutrition. Our biology, which ... in slow tiny steps, has not kept pace with the rapid changes in the way we live, and one consequence ... the epidemic of diseases of affluence, notably obesity and diabetes.