Marks: 1 During the last half of the 20th century, there has been an increase in the use of vegetable oils in exchange for dairy fat. At the same time, the consumption of fish and marine-based omega-3 polyunsaturated fatty acids (PUFAs) has decreased. Since many vegetable oils have a high content of omega-6 PUFAs, the sum effect of these changes is a considerably higher ratio of omega-6 to omega-3 in food globally, so that the presumed 'ideal' ratio of 1:1 is now: Choose one answer. a. 10-15:1 b. 2:1 c. 15-20:1 d. 5:1