What are the two adjectives in the sentence dogs can detect sound at a higher frequency than humans; therefore, they hear high pitched noises that we can't

Adjectives are descriptive words, so "higher" and "high"

the second sentence is a great revision in my opinion. that would be a great topic.

explanation:

invention of the washing machine

in the past, people used sticks and stones or scrub boards to clean their clothing. as it was sweaty, backbreaking work, we owe a world of to james king because he created the model for the modern washing machine in 1851. the most important issue was that this machine cleaned clothes while a person cranked the handle. doing this made people who used it develop strong muscles in their arms. later, in 1908, alva j. fisher created an electric washing machine named thor. this one was not the first automatic washing machine. however, it was one of the most popular models at the time.