<span>So we want to know what kind of wave is the scientist is studying while studying earthquakes. Waves that produce earthquakes are mechanical waves. Gamma rays and radiowaves are both electromagnetic waves and don't require a medium but mechanical do. So the correct answer is mechanical waves.</span>
It can be noted that the directions west and north are perpendicular to each other. hence we can use the right angle formula for calculating total distance in these directions. Also South is just negative north. This technique is called euclidean distance norm. It is the basis of Cartesian coordinate system.
Total distance = 3.22 N + 4.75 W +1.90 S
= 1.32 N + 4.75 W
D = 
D = 4.93 Km
direction = atan(N/W) = 15.53 deg north of west
Gas because liquids and solids volumes don't change from switching containers.
Systemic circulation is between the heart and the rest of the body. Therefore arteries and veins are needed.