An important step toward a more complete understanding of blackbody radiation occurred when Max Planck developed a theory that presented which
of the following ideas?
A. Light is composed of discrete chunks that must be absorbed as a
unit.
B. Large objects can be viewed as acting as waves.
C. Electrons can act as both waves and particles.
D. Matter is composed of discrete chunks that cannot be broken
down.

The correct option is;

C. Electrons can act as both waves and particles

Explanation:

The quantum theory theory developed by Max Planck established that effect of radiation on a blackbody can be explained by the fact that energy can exhibit physical characteristics which implies that energy can have both wave-like and physical characteristics

With Planck's law, light and electrons are known as having wave particle duality, that is they can act as both waves and particles.

unlike poles attract

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle