Question

1. what change, if any, needs to be made in sentence 4?

change that to it
insert a comma after mainland
change is now submerged to was now submerged
no change is needed.

Explanation:

To solve this, we analyze each option:

• "Change that to it": Without seeing sentence 4, we assume context. But typically, "that" vs "it" depends on reference. However, the other options have more obvious issues.
• "Insert a comma after mainland": Comma insertion here is unnecessary unless for a non - restrictive clause, which isn't indicated.
• "Change is now submerged to was now submerged": "Was now" is grammatically incorrect as "now" implies present, and "was" is past. So this is wrong.
• Since the other options are incorrect, the correct choice is that no change is needed.

Answer:

D. No change is needed.