Answer:
8.8 cm
31.422 cm/s
Explanation:
m = Mass of block = 0.6 kg
k = Spring constant = 15 N/m
x = Compression of spring
v = Velocity of block
A = Amplitude
As the energy of the system is conserved we have

Amplitude of the oscillations is 8.8 cm
At x = 0.7 A
Again, as the energy of the system is conserved we have

The block's speed is 31.422 cm/s
Answer:
tectonic plates move in opposite direction
Tectonic plates are not necessarily moving in opposite directions, but if there directions are different they form plate boundaries. If they were moving in the same direction they would become the same plate. The more opposite the direction, the more obvious the fault.
Examples of plate boundaries:
Divergent: moving away from each other - mid-Atlantic ridge
Convergent: moving towards each other - the Himalayas (Indian plate subducting under the Eurasian plate forcing up the mountains)
Transform: sliding laterally along each other - San Andreas fault
The sun is made mostly up of Hydrogen.
I'm guessing c because the others are pointless