"One indication that some commonly observed physical change linked to age is a product of secondary aging is that ."

It does not occur in all adults

Explanation:

One indication that some commonly observed physical change linked to age is a product of secondary aging is that it does not occur in all adults

some commonly observed physical change that is most times linked to aging is classified as a product of secondary aging because they might not be seen on some adults whom might be of the same age bracket with people who manifest those physical changes and this is because of the differences in body types and in some cases due to the health status and lifestyle of the individuals

The probability is 0.97682

Step-by-step explanation:

We start by finding the z-values of the runner times given.

Mathematically;

z-score = (x-mean)/SD

From the question, mean = 13 seconds and SD = 0.3 seconds

So for 12.4 seconds, we have;

z = (12.4-13)/0.3 = -0.6/0.3 = -2

For 14 seconds, we have;

z = (14-13)/0.3= 1/0.3 = 3.33

So the probability we want to calculate is;

P(-2<z<3.33)

We can find this using the standard normal distribution table

Mathematically;

P(-2<z<3.33) = P(z<3.33) - P(z < -2)

Using the standard normal distribution table, the value of this is;

P(-2<z<3.33) = 0.97682