You have been given a sample tissue that has pillar-shaped cells arranged tightly together. The tissue you have is:

Correct Answer: C

Rationale: The correct answer is C: Columnar Epithelium. Columnar epithelium is characterized by tall, pillar-like cells that are closely packed together. This arrangement allows for absorption and secretion in tissues like the digestive tract, where this type of epithelium is commonly found. Squamous epithelium (choice A) consists of flat cells, cuboidal epithelium (choice B) has cube-shaped cells, and transitional epithelium (choice D) is found in areas that need to stretch and expand, like the urinary bladder.

Correct Answer: B

Rationale: Proximal refers to a position closer to the point of attachment or origin. In this case, the shoulder is closer to the point of attachment to the body compared to the elbow, making it proximal to the elbow. 'Posterior' refers to the back side of the body, 'distal' means farther away from the point of attachment, and 'medial' refers to the middle of the body. These terms do not accurately describe the relationship between the shoulder and the elbow in this context.

Correct Answer: C

Rationale: The correct answer is C: frontal. The coronal plane of the body is also known as the frontal plane. This plane divides the body into front (anterior) and back (posterior) sections. It is perpendicular to the sagittal plane and divides the body into front and back portions. The term 'coronal' is often used in radiology and anatomy to describe this specific anatomical plane. Choices A, B, and D are incorrect because the sagittal plane divides the body into left and right portions, the median plane is another name for the sagittal plane, and the axial plane is a term less commonly used to describe an anatomical plane.

Correct Answer: C

Rationale: The correct answer is C: 26. The human foot consists of 26 bones, including tarsal bones, metatarsal bones, and phalanges. These bones collaborate to offer support, flexibility, and stability for various activities like standing, walking, and running. Choice A (6) is incorrect as it is too low for the number of bones in the human foot. Choice B (16) is incorrect as it underestimates the actual number of bones in the foot. Choice D (36) is incorrect as it overestimates the number of bones in the human foot.

Correct Answer: A

Rationale: Gallstones become most problematic when they block a duct, such as the bile duct or cystic duct. This blockage can lead to various complications, including inflammation, infection, and even damage to the gallbladder or liver. In severe cases, a blocked duct can cause intense pain, jaundice, and other serious symptoms that require medical intervention. Choices B, C, and D are incorrect because the presence of cholesterol or bilirubin in gallstones or the process of dissolution do not necessarily indicate when gallstones become most problematic. The critical issue arises when the stones obstruct a duct, leading to complications.

Correct Answer: B

Rationale: The retinas belong to the nervous system. The retina is a layer of tissue at the back of the eye responsible for detecting light and sending visual information to the brain through the optic nerve. This process is essential for vision, which is controlled by the nervous system. Choices A, C, and D are incorrect because the retinas have no association with the skeletal, lymphatic, or circulatory systems.

Correct Answer: A

Rationale: Selenium is the correct answer. It is considered an antioxidant mineral that plays a crucial role in protecting cells from damage caused by free radicals. Selenium is an essential component of the body's antioxidant defense system, promoting overall health and well-being. Calcium (Choice B), Sulfur (Choice C), and Iron (Choice D) are not typically classified as antioxidant minerals. While these minerals have other important functions in the body, they do not primarily act as antioxidants like selenium.

Correct Answer: A

Rationale: The frontal lobe of the brain, specifically the left hemisphere in an area known as Broca's area, is responsible for controlling speech production. This region plays a vital role in speech formation and language expression. Damage to the frontal lobe, particularly Broca's area, can lead to language difficulties like expressive aphasia, a condition characterized by trouble speaking fluently. The parietal lobe is more involved in processing sensory information and spatial awareness. The temporal lobe is associated with memory, hearing, and language comprehension. The occipital lobe is primarily responsible for processing visual information.

Correct Answer: A

Rationale: Thiamine is another name for Vitamin B1. It is an essential vitamin that plays a crucial role in energy metabolism and is important for the proper functioning of the nervous system. Vitamin B2 is riboflavin, not thiamine. Vitamin B6 is pyridoxine, not thiamine. Vitamin D is a different vitamin responsible for calcium absorption and bone health, not thiamine. Therefore, the correct answer is Vitamin B1.