Final answer:
The answer to the question involves identifying natural phenomena that exhibit a back-and-forth pattern of motion, which is characteristic of oscillatory or periodic movements. Tides, caused by the gravitational interactions with the Moon and Sun, and seasons, which are a result of Earth's tilt and orbit, can be considered to have such a pattern, even though seasons are not a physical movement.
Step-by-step explanation:
The question, 'Name two things that move in a pattern of motion that involves shifting back and forth,' relates to objects that exhibit a type of motion known as oscillation, or periodic motion. The choices listed include various phenomena, but the correct answer is not explicitly mentioned in the question. However, using the context of oscillations provided and the patterns of motion as described in the references, we can deduce that the phenomena which move in a back and forth pattern most closely relate to the physical motions of planets during retrograde and the regular changing of tides influenced by the Moon and the Sun. Therefore, while planets and celestial bodies do have complex motions, they don't oscillate in a simple back and forth motion. Instead, tides follow a rhythmic rise and fall due to gravitational interactions, which fits the description of moving back and forth. Similarly, seasons can be seen as shifting back and forth between weather patterns, although this is not a physical movement but a temporal cycle influenced by the Earth's tilt and orbit around the Sun.