12. The equation E=MC^wedge 2 implies that A. energy and mass are interchangeable C. mass can be converted to speed B. Energy is always constant D. the speed of light is variable

The correct answer is A. energy and mass are interchangeable.<br /><br />The equation E=MC^2, derived from Albert Einstein's theory of relativity, states that energy (E) is equal to mass (M) multiplied by the speed of light (C) squared. This equation implies that mass and energy are interchangeable, as it shows that a small amount of mass can be converted into a large amount of energy, and vice versa.<br /><br />Option B, "Energy is always constant," is not correct. The equation does not imply that energy is always constant; it simply shows the relationship between mass and energy.<br /><br />Option C, "mass can be converted to speed," is not correct. The equation does not imply that mass can be converted to speed. It shows the relationship between mass and energy.<br /><br />Option D, "the speed of light is variable," is not correct. The speed of light (C) is a constant value, approximately 3 x 10^8 meters per second. The equation does not imply that the speed of light is variable.<br /><br />Therefore, the correct answer is A. energy and mass are interchangeable.