D.
The block of wood does not stop moving at any time as shown on the chart, so the answer can't be A. or C. and the speed is not increasing so it can't be B.
The answer would be "a person's skin"
hope this helps :)
Fourteen-year-old warren has undergone a rapid increase in height and weight. warren is experiencing the adolescent growth spurt
His age is around when adolescent growth spurt start. In this time, the growth hormone secretion is increased substantially, increasing the growth speed.
