Relative frequency is the absolute frequency (i.e. the number of times of the wanted result) divided by the total number of events.
In this case you have to calculate: the number of heads that came up divided by the number of times the coin was flipped.
Number of times the coin was flipped: 20
Numbef of times head came up: 7
Relative frequency: 7 / 20 = 0.35, which is the option B.
500.
Solution: 210 is 42% of X
Equation: Y = P% * X
Solving our equation for X
X = Y/P%
X = 210/42%
Converting percent to decimal:
p = 42%/100 = 0.42
X = 210/0.42
X = 500
B, because people do selective breeding to get something they want out of it. Which decreases genetic diversity, genetic diversity meaning there being less and less traits and characteristics and we wont something perfect not exactly something with traits that we dont like. However dont get me wrong, nothings perfect. But yeah.
Slope is defined as the change in y-coordinate over the change in x, so if you find the change then you can find the slope.

Thus, your slope is -6/5.
I think that the correct answer is C