Which statement best defines constructive interference? O Energy reflects back toward the source of its power. O Two waves with identical crests and troughs meet. thing O A wave appears to be at a standstill and vibrates in place O The trough of one wave matches the crest of another.​

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.