As the frequency of a wave increases... A.)the energy carried by the wave decreases
B.)the wavelength of the wave decreases
C.)the amplitude of the wave decreases
D.)the speed of the wave increases

i think the answer is a, hope this is right, that would be my best guess.

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.