Please choose the correct answer to the question: What is an example of humans building houses in a ecosystem and causing change in the environment as a result?

Answer1: a dog house is placed in a fenced in back yard Answer2: a birdbath is placed in a park with a low squirrel population Answer3: a city is built over a park and deer lose their home Answer4: a small house is built in the forest and animals are fed there

Answer format: answer1/answer2/answer3/answer4