(2) She became a double eyelid through surgery, but the genes controlling eyelid traits in the body have not changed, so it is a hereditary variation. Therefore, her double eyelid traits cannot be passed on to future generations, because the genetic material in her body has not changed.
(3) According to the genetic composition of parents in the above picture, we can know that the genetic composition of child ① is AA, with double eyelids.
(4) Chromosomes in human cells are divided into autosomes and sex chromosomes. Autochromosomes are all chromosomes except sex chromosomes. There are 46 normal chromosomes (23 pairs), of which 22 pairs are called autosomes, which are the same for men and women. The 23rd pair is called sex chromosome, and human sex is mainly determined by sex chromosome. A pair of sex chromosomes in male somatic cells is XY, and a pair of sex chromosomes in female somatic cells is XX. The chromosome composition of male somatic cells can be expressed as 44+XY. The chromosome composition of female egg cells can be expressed as. Therefore, the sex chromosome composition of normal male somatic cells is XY, and that of female is XX.
(5) Dominant genes control dominant traits, while recessive genes control recessive traits. When one of the genes controlling a trait is dominant and the other is recessive, only the traits controlled by the dominant gene are displayed. It is known that double eyelids are controlled by dominant gene (a) and single eyelids are controlled by recessive gene (a). So Xiao Ming's father has double eyelids, and the genotype may be AA or AA. The mother's single eyelid is controlled by recessive gene A, so the mother's genotype is aa. So Xiaoming's father's genetic makeup is BB or BB. Xiao Ming himself has a single eyelid and the genotype is AA. One gene A comes from his father and the other from his mother, so Xiaoming's father's genotype is AA. So I chose C.
So the answer is: (1) heredity (2) incompetence (3) aa (4) xy (5) c.