Correct Answer: C

Rationale: The correct answer is 'Motility.' Motility refers to the ability of cells or organisms to move by themselves, often through the use of specialized structures like flagella or cilia. Mitosis (Choice A) and Meiosis (Choice B) are processes related to cell division and genetic recombination, respectively, not self-propulsion. Mutation (Choice D) refers to changes in the DNA sequence and is not related to self-propulsion.

Correct Answer: B

Rationale: The correct answer is B: 'The mother is Rh negative, and the father is Rh positive.' Hemolytic disease of the newborn occurs when an Rh-negative mother carries an Rh-positive fetus, leading to Rh incompatibility. In this scenario, the mother produces antibodies against the Rh antigen present in the fetus, which can result in hemolysis of the fetal red blood cells. Choices A, C, and D do not describe the Rh incompatibility that leads to hemolytic disease in newborns. Therefore, they are incorrect.

Correct Answer: A

Rationale: Tay-Sachs disease is a genetic disorder that causes a progressive degeneration of the central nervous system, particularly in infants. Choice B, Cystic fibrosis, is a genetic disorder that primarily affects the lungs and digestive system, not the central nervous system. Choices C and D, Turner syndrome and Klinefelter syndrome, are chromosomal disorders that do not directly involve degeneration of the central nervous system.

Correct Answer: C

Rationale: Down's syndrome, also known as trisomy 21, is caused by the presence of an extra chromosome on the 21st pair. Choice A is incorrect as alcohol abuse is not the cause of Down's syndrome. Choice B is incorrect because Down's syndrome is not related to sex-linked chromosomal abnormalities. Choice D is also incorrect as drug abuse by the mother during pregnancy is not the cause of Down's syndrome.

Correct Answer: A

Rationale: During the first stage of labor, effective uterine contractions lead to cervical dilation. Dilation of the cervix is a key indicator that uterine contractions are progressing labor. Descent of the fetus to -2 station (Choice B) is related to the fetal position in the pelvis and not a direct indicator of uterine contraction effectiveness. Rupture of the amniotic membranes (Choice C) signifies the rupture of the fluid-filled sac surrounding the fetus and does not directly reflect uterine contraction effectiveness. An increase in bloody show (Choice D) can be a sign of impending labor, but it is not a direct indicator of uterine contraction effectiveness.