How should the sentence below be changed?

corbin enjoys going to the grocery store therefore, he does all of the grocery shopping.

add a semicolon after store
remove the comma after therefore
add a comma after corbin
change the period to a question mark

add a semicolon after store

To form soil, the two processes which must occur are erosion and weathering, so the correct answer is "soil formation is a continuous presses, but also one which takes a long time, it can sometimes take more than five hundred years for 1cm of soil to form.