Answer:
The error is "Earths rotation".
Step-by-step explanation:
This sentence has a possessive error. As we know, in the English language we can use the genitive case to establish a relationship of possession between two or more people or things. The genitive case is mostly formed by adding 's to the possessor. In the sentence, however, the ' was left out, and only the letter "s" was added to "Earth". By doing that, we transformed "Earth" into a plural word and did not indicate the possession necessary for the sentence to make sense. The correct form would be:
The rising and falling tides are caused by the gravitational pull of the moon and sun, as well as Earth's rotation.