is the bending of waves as they pass by a barrier or through an opening. A. Interference
B. Coherence
C. Diffraction
D. None of the above

C. Diffraction

Explanation:

Diffraction is the bending of waves as they pass by a barrier or through an opening. One of the condition for diffraction is that the size of the aperture or obstacle is comparable to the wavelength of light. Fresnel diffraction and Fraunhofer diffraction are two types of diffraction.

Hence, the correct option is (c) "Diffraction".

- measure reactants precisely. ( first choice)

- stir to the reaction take place. ( second choice)

- wait patiently until the reaction completes. ( fourth choice)

- make sure to recover as much copper as possible. ( last choice)

probably not if net force is zero