Let's say I've got an apple, a banana, and an orange.
Which of the following are ok, if any?
I've got an apple, banana, and an orange.
I've got an apple, banana, and orange.
The actual sentence I'm editing is: "... in sandy soil with either a moss, an algae, or a sandy surface". I'm wondering if the "an" before algae and the "a" before sandy surface are necessary. Are there any other ways of writing this? What formal rule does this involve?