1. The influences are more in your genes of nature because your parents reproduced and when they have the baby the both 50% of there genes goes in to you and it wouldn't be nurture because your genes are sexually produced and then applied to you which is naturally done. This goes through the process of creating the baby in the girls body, with no supplement needed for the growing and the creation of the baby.
2. If DNA does not copy itself correctly the cells would form mutations that could be in many reasons good bad or just wouldn't affect the cells, but in many cases the mutation would be bad and could cause many different deceases such as cancer. Cancer is caused by many different cells going through mitosis and that they cant stop reproducing so it cant stop and then forms a tumor that may o may not be good or bad cancer. Also if the DNA would be different it would cause that you would have many different characteristics that you already have.
3. First the advantage of asexual reproduction is that when you are conceived you grow to be a baby in only 4 months while a human baby would last about 9 months in the parent! But the disadvantage is that you would look exactly like your parent and if your parent would have other children they would look exactly the same as you. The advantage of sexual reproduction is that when you are in your parent body all there nutrients go to you and the disadvantage is that you take 9 months to be born,