Correct Answer: B

Rationale: During the transition phase of labor, a client may experience intense back pain due to the pressure of the baby descending. Applying counterpressure to the client's sacrum can help alleviate this discomfort. Effleurage is a light stroking massage technique that may not provide adequate relief for intense back pain. Patterned-paced breathing is beneficial for managing contractions but may not directly address back pain. Biofeedback is a technique that helps individuals gain awareness and control of certain physiological functions, but it may not be the most appropriate intervention for acute labor pain.

Correct Answer: D

Rationale: Hegar's sign, which is a softening of the lower uterine segment, is considered a probable sign of pregnancy as it indicates changes in the cervix and uterus that occur during pregnancy. Amenorrhea, the absence of menstruation, is a common early sign of pregnancy but can also be due to other factors. Morning sickness, nausea and vomiting, can be a sign of early pregnancy but is not as specific as Hegar's sign. Breast tenderness is a common symptom in early pregnancy due to hormonal changes, but it is not as definitive as Hegar's sign in indicating pregnancy.

Correct Answer: D

Rationale: Chlamydia infection is a significant risk factor for developing pelvic inflammatory disease (PID). PID is often caused by untreated sexually transmitted infections (STIs) like Chlamydia and Gonorrhea that ascend from the vagina to the upper reproductive organs. Recurrent cystitis (choice A) is more related to urinary tract infections, frequent alcohol use (choice B) is not directly linked to PID, and the use of oral contraceptives (choice C) does not increase the risk of developing PID.

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: Adenine. In the structure of DNA, adenine pairs with thymine through hydrogen bonding, forming one of the complementary base pairs that make up the double helix structure of DNA. Cytosine pairs with guanine, not thymine. Rhodamine and serine are not DNA bases and do not participate in DNA base pairing. Therefore, choices A, C, and D are incorrect.