D: All the variables are controlled except one.
You should ask your teacher to be sure, but I think that you teacher meant like the mode of transmission.... Like genetically inherited and such.
"Meiosis II is not completed until after the egg cell makes contact with the sperm cell." This is false because, for both genders, meiosis splits into haploid cells. The end of Meiosis II would be when the four haploid cells are separated.
A sample is a random, unbiased selection out of a larger group. An independent variable is one that is changed as to see how it will affect the dependent variable in an experiment.
Hope that helped.
