1. The microscopic units responsible for muscle contraction are called

A. Neurons
B. Myofibrils
C. Tendons
D. Sarcomeres

Correct answer: D

Rationale: The correct answer is D: Sarcomeres. Sarcomeres are the fundamental contractile units of skeletal muscle. They are composed of overlapping actin and myosin filaments that slide past each other during muscle contraction, resulting in muscle shortening. Neurons (A) are nerve cells that transmit signals to and from the brain. Myofibrils (B) are thread-like structures within muscle fibers that contain sarcomeres. Tendons (C) are fibrous connective tissues that attach muscles to bones, but they are not directly involved in muscle contraction like sarcomeres are.

2. What is the main function of the epiglottis, a small flap of cartilage located above the larynx?

A. To warm and humidify inhaled air
B. To control the passage of food and air
C. To produce sound vibrations for speech
D. To sense the presence of foreign objects

Correct answer: B

Rationale: The correct answer is B: 'To control the passage of food and air.' The epiglottis is a crucial structure that prevents food and liquids from entering the airway during swallowing. It acts as a lid over the trachea, ensuring that food goes down the esophagus while air passes into the respiratory system. This function is essential for preventing choking and ensuring proper breathing. Options A, C, and D are incorrect as the epiglottis is not primarily responsible for warming and humidifying inhaled air, producing sound vibrations for speech, or sensing foreign objects.

3. What is the term for a solution that has a higher concentration of solute compared to another solution?

A. Saturated solution
B. Unsaturated solution
C. Dilute solution
D. Concentrated solution

Correct answer: d

Rationale: A concentrated solution has a higher concentration of solute compared to another solution. The other choices do not accurately describe a concentrated solution.

4. The free edges of your fingernails and toenails are technically called the:

A. Lunula (The lunula is the white crescent moon shape at the base of the nail)
B. Matrix (The matrix is the area under the nail where new nail cells are produced)
C. Hyponychium (This is the skin under the free edge of the nail)
D. Free edge

Correct answer: D

Rationale: The free edges of your fingernails and toenails are the parts that extend beyond the fingertip or toe. These edges are commonly referred to simply as the "free edge" because they are not attached to the skin. The lunula is the white crescent moon shape at the base of the nail, the matrix is the area under the nail where new nail cells are produced, and the hyponychium is the skin under the free edge of the nail. Therefore, the correct answer is D.

5. What is the primary function of the coronary arteries in the cardiovascular system?

A. Carry oxygenated blood to the heart muscle
B. Carry deoxygenated blood from the heart muscle
C. Pump blood to the lungs for oxygenation
D. Regulate blood pressure in the systemic circulation

Correct answer: A

Rationale: The primary function of the coronary arteries in the cardiovascular system is to carry oxygenated blood to the heart muscle. These arteries supply the heart muscle with the necessary oxygen and nutrients it needs to function properly. Without adequate blood flow through the coronary arteries, the heart muscle can become deprived of oxygen, leading to conditions like angina or even a heart attack. Options B, C, and D are incorrect as they do not accurately describe the function of the coronary arteries. Option B is incorrect because the coronary arteries carry oxygenated blood, not deoxygenated blood. Option C is incorrect because the pulmonary arteries, not the coronary arteries, carry blood to the lungs for oxygenation. Option D is incorrect because the regulation of blood pressure in the systemic circulation is primarily controlled by mechanisms such as the kidneys and the autonomic nervous system, not the coronary arteries.

6. Lymph nodes, found along lymphatic vessels, are important for:

A. Storing blood
B. Producing antibodies
C. Filtering lymph and trapping harmful substances
D. All of the above

Correct answer: D

Rationale: The correct answer is D, 'All of the above.' Lymph nodes are important for various functions in the immune system. They filter lymph, trapping harmful substances like bacteria and viruses, which helps in preventing infections. Lymph nodes also play a crucial role in producing antibodies, which are essential for fighting off pathogens. Additionally, lymph nodes do not store blood; that is the function of the spleen. Therefore, the correct answer is D because lymph nodes perform all the mentioned functions in supporting the body's immune response.