A "folk" remedy is something you choose to eat, take, or do,
in order to correct some health issue, because your friend,
your grandmother, your religion, your shaman, your astrologer,
or your medicine man says that it's the right thing to do.
It may or may not be effective, and it may or may not even be
safe. What distinguishes it from mainstream medicine is that
its practices are based on hearsay, and have not been subjected
to scientific methods of investigation and evaluation.
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(a) 
The frequency of a wave is given by:

where
v is the wave's speed
is the wavelength
For the red laser light in this problem, we have
(speed of light)

Substituting,

(b) 427.6 nm
The wavelength of the wave in the glass is given by

where
is the original wavelength of the wave in air
n = 1.48 is the refractive index of glass
Substituting into the formula,

(c) 
The speed of the wave in the glass is given by

where
is the original speed of the wave in air
n = 1.48 is the refractive index of glass
Substituting into the formula,

energy never disappears, for example, if you give some kinetic energy to a ball and it stops few seconds later, friction steals this energy to ground which ball was going on. "Law of Conservation of Energy" tell us that energy can't disappear
The animals need less food people it is winter time.