Correct Answer: D

Rationale: Cilia are not part of the body's secondary defense system. They are hair-like structures primarily involved in movement and transporting substances across cell surfaces, such as in the respiratory tract for debris and pathogen removal. However, cilia do not play a direct role in the immune response mechanisms characteristic of the body's secondary defense system. Macrophages, leukocytes, and T cells are immune cells that actively participate in the secondary defense system by targeting and eliminating pathogens.

Correct Answer: D

Rationale: The correct answer is the Achilles tendon. The Achilles tendon is a strong tendon located at the back of the human leg, connecting the calf muscles to the heel bone. This positioning makes it a posterior feature, situated at the rear of the leg. The patella, also known as the kneecap, is positioned at the front of the leg, making it an anterior feature. The quadriceps sartorius are muscles located in the front of the thigh, not at the back of the leg. Additionally, the triceps brachii is a muscle found in the upper arm, not in the leg, making it an incorrect choice.

Correct Answer: B

Rationale: The correct answer is B: The pulmonary artery carries blood from the heart to the lungs. The first step in pulmonary circulation involves the right ventricle of the heart pumping deoxygenated blood into the pulmonary artery. The pulmonary artery then carries this deoxygenated blood from the heart to the lungs for oxygenation. This step is crucial for the exchange of carbon dioxide for oxygen to occur in the lungs, facilitating the oxygenation of blood. Choices A, C, and D are incorrect because they do not represent the initial step in pulmonary circulation. Option A refers to blood moving away from the heart, option C describes the gas exchange process that occurs in the lungs but not as the first step, and option D mentions oxygenated blood moving through the aorta, which happens after oxygenation in the lungs.

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: C

Rationale: The correct answer is C: Humerus and scapula. The rotator cuff is a group of muscles and tendons that help stabilize the shoulder joint. Specifically, the rotator cuff muscles help to stabilize the head of the humerus (the upper arm bone) within the shallow socket of the scapula (shoulder blade). This stabilizing action is crucial for maintaining shoulder joint function and preventing injuries. Choices A, B, and D are incorrect because the rotator cuff primarily stabilizes the humerus and scapula, not the radius, ulna, or clavicle.