surface or surfaces

[Nie]

Hello :)

Are these sentences correct?

A: Most of the Earth's surface is covered with water.

B: The Earth's surface is mostly covered with water.

Thanks a lot :)

[Eugene2114]

I think both are correct though they differ in meaning:
Most: "to the highest degree"
Mostly: "mainly" / the main thing that covers the Earth is water, in your example/
More examples: The 3-year-olds were most affected by the artificial food / they were very affected/
The 3-year-olds were mostly affected by the artificial food /the main thing that affected them was the food/
Regards.

[Vuqar1.618]

hi Nie
they both are grammatically correct.But there is a little difference in meaning between
them.