Cilia is abundant in the:

Correct Answer: C

Rationale: The correct answer is C: Fallopian tube. Cilia are hair-like structures that line the fallopian tube to help move the egg from the ovary to the uterus. This movement is crucial for fertilization to occur. The other choices, A, B, and D, are incorrect because cilia are not typically abundant in the urinary tract, intestinal tract, or male reproductive ducts, respectively. These regions do not require the same kind of movement facilitated by cilia in the fallopian tube.

Correct Answer: C

Rationale: The correct answer is C: Hyaline cartilage. This type of cartilage is found at the ends of long bones in synovial joints because it provides a smooth surface for articulation, reducing friction and allowing for smooth movement. Hyaline cartilage is the most common type of cartilage in the body and is characterized by its glassy appearance and ability to withstand compressive forces. Fibrocartilage (choice A) is found in intervertebral discs and has more collagen fibers, making it tougher but less flexible than hyaline cartilage. Elastic cartilage (choice B) contains more elastic fibers and is found in structures like the external ear and epiglottis, providing flexibility and resilience. Cellular cartilage (choice D) is not a recognized type of cartilage and is an incorrect choice.

Correct Answer: D

Rationale: Step-by-step rationale for why choice D is correct: 1. During early development, all embryos possess indifferent genitalia. 2. Androgen hormones, like testosterone, influence the differentiation of these structures. 3. The presence of androgen hormones leads to the development of male genitalia. 4. Lack of androgen results in the development of female genitalia. 5. This process occurs after fertilization, not during fertilization. In summary, choice D is correct as the phenotypic sex is determined by the activity of androgen hormones on the indifferent genitalia post-fertilization. Choices A and B are incorrect because sex determination occurs post-fertilization, not during fertilization. Choice C is incorrect as the SRY gene typically plays a role in sex determination but is not the primary factor influencing the phenotypic sex.

Correct Answer: B

Rationale: The correct answer is B: Normal amniotic fluid volume. An amniotic fluid index of 18 cm in the 3rd trimester is considered within the normal range (5-25 cm). This level indicates adequate amniotic fluid for fetal development and is not indicative of hydrops fetalis (A), reduced amniotic fluid volume (C), or increased amniotic fluid volume (D). It is crucial to monitor amniotic fluid levels as deviations from the normal range can impact fetal well-being.

Correct Answer: B

Rationale: The correct answer is B: Clavicle and scapula. The pectoral girdle consists of the clavicle (collarbone) and the scapula (shoulder blade). The clavicle articulates with the sternum, providing a connection between the upper limb and the axial skeleton. The scapula forms the shoulder joint with the humerus. The sternum is part of the axial skeleton and not directly part of the pectoral girdle. The humerus is a bone of the upper arm and not part of the pectoral girdle. Therefore, the correct answer is B as it accurately represents the bones that make up the pectoral girdle.