Question 125751
Part of this is biology.
A girl has the chromosome XX and a boy has XY.
For qn 1, the answer is 1/2 because all the XX squares (2 of them out of 4) are shaded.
Same for qn 2, probability is also 1/2 because all the XY squares (2 out of 4) are shaded.
For qn 3, the father will determine the sex of the child because the father has both the X and Y in his chromosome while the mother has both XX. The mother always gives a X to the child but the father can either give X or Y, thus determining the sex of the child.
hope this answers your query.