Correct Answer: C

Rationale: The correct definition of the anatomical term 'medial' is being close or near to the midline of the body. This term describes a position closer to the center or midline of the body, opposite to 'lateral' which refers to a position further away from the midline. Choice A, 'Being face down,' is incorrect as it describes the anatomical term 'prone.' Choice B, 'On the front of the body or limb,' is incorrect as it describes the anatomical term 'anterior.' Choice D, 'Above or on top of the lungs,' is incorrect as it does not relate to the term 'medial.'

Correct Answer: D

Rationale: All of the statements are correct regarding heart valves. Choice A is accurate as the atrioventricular valves indeed lie between the atria and the ventricles. Choice B correctly identifies the location of the pulmonary semilunar valve. Choice C is true as the atrioventricular valves do prevent backflow into the atria during ventricular contraction. Therefore, selecting 'All of the above' as the correct answer is appropriate as all statements are accurate.

Correct Answer: A

Rationale: The correct answer is A: Arteries. Arteries are the large blood vessels that carry blood away from the heart to various parts of the body. They have thick, muscular walls to withstand the high pressure generated by the heart's pumping action. Choice B, Arterioles, are smaller branches of arteries that further divide into capillaries. Choice C, Veins, carry blood back to the heart and have thinner walls compared to arteries. Choice D, Venules, are smaller veins that collect blood from capillaries and merge into larger veins.

Correct Answer: A

Rationale: KCl exemplifies an ionic bond. In an ionic bond, electrons are transferred between atoms, resulting in the formation of ions. In the case of KCl, potassium (K) donates an electron to chlorine (Cl), leading to the creation of K+ and Cl- ions, which are held together by electrostatic forces of attraction. Choice B, covalent bond, is incorrect because covalent bonds involve the sharing of electrons between atoms, not the transfer of electrons as seen in KCl. Choice C, hydrogen bond, is incorrect as hydrogen bonds are a type of intermolecular force, not a bond formed by the transfer or sharing of electrons between atoms. Choice D, polar covalent bond, is also incorrect because although it involves the sharing of electrons with an unequal distribution of charge, KCl is a clear example of ionic bonding where electrons are completely transferred.

Correct Answer: B

Rationale: The small intestine is the primary site for nutrient absorption in the digestive system. It is lined with specialized cells that facilitate the absorption of nutrients such as carbohydrates, proteins, fats, vitamins, and minerals into the bloodstream for distribution throughout the body. While the stomach plays a role in digestion by breaking down food with acid and enzymes, the actual absorption of nutrients occurs mainly in the small intestine. The esophagus is responsible for transporting food from the mouth to the stomach, but it does not absorb nutrients. The large intestine primarily absorbs water and electrolytes, not nutrients.