Correct Answer: B

Rationale: The correct answer is 'Nephrons.' Nephrons are the structural and functional units of the kidneys responsible for creating and transporting urine. Each kidney contains thousands of nephrons located in the cortex and medulla. The nephron consists of the renal corpuscle, which includes the glomerulus, and the renal tubule, which consists of the proximal tubule, loops of Henle, and distal tubule. While the glomerulus, loops of Henle, and distal tubules are all parts of the nephron, the nephrons as a whole are specifically responsible for creating and transporting urine.

Correct Answer: C

Rationale: The correct answer is C: Protein. Hemoglobin is a protein responsible for carrying oxygen in the blood. Proteins are macromolecules made up of amino acids and play a vital role in various biological functions, including the transportation of molecules like oxygen. Choices A, B, and D are incorrect because carbohydrates, lipids, and nucleic acids are different types of macromolecules that have distinct structures and functions. Carbohydrates are mainly involved in energy storage and structural support, lipids are essential for energy storage and cell membrane structure, and nucleic acids are responsible for storing and transmitting genetic information.

Correct Answer: C

Rationale: When the pressure in the pulmonary artery is increased above normal, the right ventricle of the heart will be affected first. The right ventricle is responsible for pumping blood into the pulmonary artery, which carries deoxygenated blood to the lungs for oxygenation. Increased pressure in the pulmonary artery can result in increased workload on the right ventricle as it tries to pump blood against higher resistance, leading to potential strain and dysfunction in the right ventricle. Choices A, B, and D are incorrect because the right ventricle is the chamber directly connected to the pulmonary artery, and it bears the immediate impact of any changes in pressure within this artery. The right atrium receives deoxygenated blood from the body and the left atrium receives oxygenated blood from the lungs, while the left ventricle pumps oxygenated blood to the body and the right ventricle pumps deoxygenated blood to the lungs.

Correct Answer: C

Rationale: The correct answer is C: Posterior. 'Posterior' is the anatomical term that refers to the back of the body. It is the opposite of 'anterior,' which refers to the front of the body. 'Superior' typically describes a structure that is positioned above another structure, while 'inferior' refers to a structure that is below another. In this case, the term 'posterior' specifically indicates the back of the body, making it the most appropriate choice among the options provided.

Correct Answer: D

Rationale: An isotope of an element is an atom with a different number of neutrons, resulting in a different mass number. Isotopes of the same element have the same number of protons (which determines the element's identity) but differ in the number of neutrons, leading to variations in mass numbers. Choice A is incorrect because isotopes of the same element have the same atomic number. Choice B is incorrect because isotopes of the same element have the same number of protons. Choice C is incorrect because isotopes of the same element have the same number of electrons.