D. rates of soil erosion are much lower during droughts that last several years
First we gotta use an equation of motion:

Our vertical distance d= 100 m, initial vertical speed u = 0 m/s (because velocity is fully horizontal), and vertical acceleration a = 9.8 m/s2 because of gravity. Let's plug it all in!

Now we just need to solve for t:

Hit the calculators, and you'll get 4.5 seconds!
If a surface looks "shiny" to you, that's because it reflects all
or most of the visible light that hits it. That doesn't always mean
that the same surface reflects other, non-visible wavelengths of
light. Infrared radiation may also reflect off of it, and probably
does. But you can't be sure just because it's visibly shiny.
Fish swimming forward in the water, the water gets pushed backward because the fish moving forward is forcing the water to move backward, the motion forward and backward are the same, they are opposite and equal.