Which sentence contains an element of bias?

research shows that eating fruits and vegetables reduces a person’s risk of heart disease.
fruits and vegetables contain a variety of vitamins and minerals that are essential to a healthy diet.
most fruits and vegetables are low in calories, making them a healthy and delicious part of any diet.
studies show that eating whole fruits and vegetables is healthier than drinking juice, which often has added sugar.

onto a large boat, and mark the water level that the boat sinks to. then, take the elephant out and put a bunch of marked weights onto the boat until it reaches the same water level. add up the masses of the weights to get the weight of the elephant.

substitute y = 2x - 4 to x + 2y = 12:

x + 2(2x - 4) = 12     use distributive property

x + (2)(2x) + () = 12

x + 4x - 8 = 12     add 8 to both sides

5x = 20     divide both sides by 5

x = 4

put the value of x to the first equation:

y = 2(4) - 4

y = 8 - 4

y = 4