Answer:
D
Explanation:
If you list and compare, the elephants hearing range is the closest to a humans.
Humans: 20-20,000
Elephant: 16-12,000
While the others are either too much more or less than a humans.
Bat: 2,000-110,000
Dolphin: 90-105,000
Chicken: 125-2,000
Through a dam... hope this helps:)
A. A child rubs a balloon
Answer:
Distance: 21 yd, displacement: 15 yd, gain in the play: 12 yd
Explanation:
The distance travelled by Sam is just the sum of the length of each part of Sam's motion, regardless of the direction. Initially, Sam run from the 3 yd line to the 15 yd line, so (15-3)=12 yd. Then, he run also 9 yd to the right. Therefore, the total distance is
d = 12 + 9 = 21 yd
The displacement instead is a vector connecting the starting point with the final point of the motion. Sam run first 12 yd straight ahead and then 9 yd to the right; these two motions are perpendicular to each other, so we can find the displacement simply by using Pythagorean's theorem:

Finally, the yards gained by Sam in the play are simply given by the distance covered along the forward-backward direction only. Since Sam only run from the 3 yd line to the 15 yd line along this direction, then the gain in this play was
d = 15 - 3 = 12 yd
Water expands when it freezes (that's why you should never put closed, fully filled water bottles in the freezer !)