1. During inhalation, which muscle contracts to increase the volume of the thoracic cavity, allowing air to flow into the lungs?

A. Diaphragm
B. Intercostal muscles
C. Abdominal muscles
D. Pectoral muscles

Correct answer: A

Rationale: The correct answer is A: Diaphragm. During inhalation, the diaphragm contracts and moves downward, increasing the volume of the thoracic cavity. This action creates a pressure difference between the lungs and the atmosphere, causing air to flow into the lungs. The intercostal muscles also play a role by expanding the ribcage, but the primary muscle responsible for increasing thoracic cavity volume during inhalation is the diaphragm. Abdominal muscles are involved in exhalation by contracting to push the diaphragm up, reducing thoracic cavity volume. Pectoral muscles are located in the chest and are not directly involved in the breathing process.

2. What is the main component of stomach acid?

A. Hydrochloric acid
B. Bicarbonate
C. Bile salts
D. Enzymes

Correct answer: A

Rationale: Rationale: Stomach acid, also known as gastric acid, is primarily composed of hydrochloric acid. Hydrochloric acid plays a crucial role in the digestive process by helping to break down food and kill bacteria in the stomach. Bicarbonate is a base that helps neutralize stomach acid in the small intestine. Bile salts are produced by the liver and stored in the gallbladder, aiding in the digestion and absorption of fats. Enzymes are proteins that help catalyze chemical reactions in the body, including the breakdown of food molecules during digestion.

3. Which of the following is the basic unit of the nervous system?

A. Neuron
B. Nerve
C. Ganglion
D. Neuroglia

Correct answer: A

Rationale: Rationale: Neurons are the basic structural and functional units of the nervous system. They are specialized cells that transmit information through electrical and chemical signals. Nerves are bundles of neurons, ganglia are clusters of nerve cell bodies outside the central nervous system, and neuroglia are support cells for neurons. However, neurons are specifically responsible for transmitting and processing information in the nervous system, making them the basic unit of this system.

4. Fluorescent microscopy utilizes which property of certain molecules to create a visible image?

A. Staining properties
B. Light absorption
C. Fluorescence emission
D. Refraction

Correct answer: C

Rationale: Rationale: Fluorescent microscopy relies on the property of certain molecules to fluoresce when exposed to specific wavelengths of light. When these molecules absorb light energy, they become excited and then emit light at a longer wavelength, producing a visible image. This emitted light is what is used to create the image in fluorescent microscopy, making option C, fluorescence emission, the correct answer. Staining properties (option A) are used to enhance contrast in microscopy but are not the primary mechanism in fluorescent microscopy. Light absorption (option B) is involved in the excitation of fluorescent molecules but is not the property used to create the visible image. Refraction (option D) is the bending of light as it passes through different mediums and is not the property utilized in fluorescent microscopy.

5. Which property of a wave remains constant when it crosses a boundary between two different media?

A. Frequency
B. Wavelength
C. Amplitude
D. Speed

Correct answer: d

Rationale: The speed of a wave remains constant when it crosses a boundary between two different media, although its direction may change.

6. What is the scientific name for the tear gland?

A. Lachrymal gland
B. Lacrimal sac
C. Lacrimal duct
D. Lacrimal papilla

Correct answer: A

Rationale: The lachrymal gland is the almond-shaped gland located above each eye, responsible for producing tears. Tears are a complex mixture of water, electrolytes, proteins, and other substances that help lubricate and protect the eyes from dryness and irritation.