Were studying molarity in my bio class.I thought I knew what I was doing but it keeps saying my answers are wrong.

Can someone tell me what I'm doing wrong?

If you have 58 grams of NaCl in 1 (one) Liter of water, what is the molarity of the solution?

-This is what I did. I found the molecular weight. Na was 22.990 and Cl was 35.353. I decided to round Na up to 23 and Cl to 35.5. Does the rounding affect that? After adding those togther you end up with 58.5.I then divided 58/58.5. I end up with 0.991453 so I rounded that to 0.991.Was that right?

Another question I have is this

This type of chemical solution resists changes in pH

-I thought the answer to this was A buffer solution,but it said it was wrong. Is that right?

Both of your answers sound correct to me.
Where are you getting the incorrect evaluation from?
There are some trivial potential errors but nothing major except to a computer. For instance, the question may consider 58 g of NaCl to be one mole and therefore your answer of 0.991 is seen as wrong.
Technically, to be 1.0 M you want 1 mole of NaCl dissolved in 1 liter of SOLUTION not in 1 L of water (because the solute will add to the total volume).
Buffer solutions resist changes on pH.
I say that you are correct!