Student or Learner
Last night I went shopping. I bought a watch, a bracelet ,and a necklace.
In this sentence the last comma is optional and you can omit it because it is a serial comma.
When you want to separate items in a series that contains commas we need semicolons.
My sister had a prfitable summer: by mowing lawns, she earned $125; by washing cars, $85; and by walking the neighbor's dogs, $110.
Can we omit the semicolon before and like the serial comma or no?
No. Leave it in.