The chromosomal disorder CORRECTLY matched with its karyotype is:

Correct Answer: A

Rationale: Step-by-step rationale: 1. Turner's syndrome is characterized by a missing X chromosome, resulting in a karyotype of 45X0. 2. Klinefelter's syndrome involves an extra X chromosome, leading to a karyotype of 47XXY. 3. Patau's syndrome is Trisomy 13, not Trisomy 21. 4. Edward's syndrome is Trisomy 18, not Trisomy 13. Therefore, the correct answer is A because Turner's syndrome is correctly matched with a karyotype of 45X0.

Correct Answer: B

Rationale: The correct answer is B because the morula is a stage between the zygote (fertilized egg) and blastocyst (hollow ball of cells). After fertilization, the zygote undergoes multiple rounds of cell division to form a compact cluster of cells known as the morula. This stage precedes the blastocyst stage where the cells differentiate and form an inner cell mass and outer trophoblast layer. A) After implantation is incorrect because the morula forms before implantation. C) Between the blastocyst and gastrula is incorrect as the morula occurs before the blastocyst stage. D) Between implantation and parturition is incorrect as the morula stage occurs much earlier in development.

Correct Answer: A

Rationale: The correct answer is A: Secretory phase. During the secretory phase of the menstrual cycle, the endometrial thickness is greatest due to increased progesterone levels, leading to thickening of the endometrium in preparation for potential implantation of a fertilized egg. This phase occurs after ovulation and is characterized by glandular secretions and increased vascularity to support a potential pregnancy. Summary: - Menstrual phase (B) is incorrect as it is characterized by shedding of the endometrial lining. - Proliferative phase (C) is incorrect as it involves endometrial thickening but not to the extent seen in the secretory phase. - Late follicular phase (D) is incorrect as it precedes ovulation and is primarily characterized by follicular development rather than significant endometrial thickening.

Correct Answer: C

Rationale: The correct answer is C: 7. The cervical spine consists of 7 vertebrae, labeled as C1 to C7. Each vertebra plays a vital role in supporting the head and facilitating neck movement. C1 is known as the atlas, C2 is the axis, and C3 to C7 are structurally similar cervical vertebrae. These vertebrae house the spinal cord and provide flexibility for head movements. Choices A, B, and D are incorrect because the cervical spine does not have 2, 5, or 8 vertebrae. It is crucial to understand the anatomical structure of the spine to determine the correct number of cervical vertebrae.

Correct Answer: A

Rationale: The correct answer is A: Corpus callosum. The corpus callosum is the main commissural fiber in the brain that connects the two cerebral hemispheres, allowing for communication and coordination between them. It is the largest and most prominent commissural fiber in the brain, making it the correct choice. Summary of why other choices are incorrect: B: Anterior commissure - Connects certain regions of the cerebral hemispheres, but not as prominent or as large as the corpus callosum. C: Posterior commissure - Connects certain structures in the brainstem, not the cerebral hemispheres. D: Hippocampal commissure - Connects the two hippocampi, not the cerebral hemispheres.