A heron is perched in a tree 50 feet above sea level. Directly below the heron, a pelican is flying 17 feet above sea level. Directly below the birds is a trout, swimming 23 feet below sea level.
Select all the statements that are true:
A. The difference in height between the pelican and the heron is -33 feet
B. The difference in height between the pelican and the heron is 33 feet
C. The distance between the heights of the pelican and heron is -33 feet
D. The difference in height between the pelican and the trout is -40 feet
E. The difference in height between the pelican and the trout is 40 feet
F. The distance between the heights of the pelican and the trout is 40 feet.

The difference between two points is [tex]P_1-P_2[/tex], thus the difference between the height of the Pelican and the height of the Heron is [tex]P_p-P_h = 17ft-50ft=-33ft[/tex], and between the Pelican and the trout it is [tex]P_p-P_t=17ft-(-23ft)=40ft[/tex].

The distance between two points is just the absolute value of the difference between them. Between the Pelican and the Heron it is[tex]|P_p-p_h|= 33ft[/tex], and the distance between the Pelican and the Trout is [tex]|P_p-P_t|=40ft[/tex].

Therefore,

A is correct;

B is incorrect (difference is not positive);

C is incorrect (distance cannot be negative);

D is incorrect (difference is not positive);

E is correct;

F is correct;