1. The muscular diaphragm plays a vital role in respiration. When it contracts, it:

A. Increases lung volume for inhalation
B. Decreases lung volume for exhalation
C. Filters dust and particles from inhaled air
D. Produces mucus to lubricate the airways

Correct answer: A

Rationale: The diaphragm is a crucial muscle involved in respiration. When the diaphragm contracts, it flattens and moves downwards, increasing the volume in the thoracic cavity. This expansion creates a negative pressure in the lungs, causing air to rush in during inhalation. Therefore, option A, 'Increases lung volume for inhalation,' is the correct answer. The diaphragm's contraction facilitates the breathing process by creating space for the lungs to expand and take in air, making it essential for proper respiration.

2. What is a mutation?

A. A change in the DNA sequence
B. A type of protein
C. A normal part of the DNA replication process
D. A harmless variation in DNA

Correct answer: A

Rationale: Rationale: A mutation is defined as a change in the DNA sequence. Mutations can occur due to various factors such as errors during DNA replication, exposure to mutagens (e.g., chemicals, radiation), or spontaneous changes. These changes can result in alterations to the genetic information carried by an organism, which can have different effects ranging from harmless variations to causing genetic disorders or diseases. Mutations are a fundamental aspect of genetic diversity and evolution. Options B, C, and D do not accurately describe what a mutation is.

3. Hair follicles are openings in the skin that house

A. Blood vessels (Blood vessels are not housed in hair follicles)
B. Nerve endings (Nerve endings are present but not housed within)
C. Hair shafts and hair roots
D. Sebaceous glands (These glands are often attached to hair follicles)

Correct answer: C

Rationale: Hair follicles are structures in the skin that house both the hair shaft and the hair root. The hair shaft is the visible part of the hair that extends from the skin's surface, while the hair root is the part embedded within the hair follicle and extends into the deeper layers of the skin. The sebaceous glands, which produce sebum (an oily substance), are typically attached to hair follicles and help lubricate and protect the hair and skin. Blood vessels and nerve endings are present in the skin but are not housed within the hair follicles themselves. Therefore, the correct answer is C, as hair follicles contain both the hair shaft and hair root.

4. The Minimum Inhibitory Concentration (MIC) of an antibiotic refers to:

A. The lowest concentration that kills bacteria
B. The dose required for 50% bacterial inhibition
C. The time it takes for an antibiotic to work
D. The spectrum of bacteria the antibiotic targets

Correct answer: B

Rationale: Rationale: A) The lowest concentration that kills bacteria is known as the Minimum Bactericidal Concentration (MBC), not the Minimum Inhibitory Concentration (MIC). MIC is the lowest concentration of an antibiotic that inhibits visible growth of bacteria. B) The MIC of an antibiotic is the concentration at which bacterial growth is inhibited by 50%. This concentration is used to determine the effectiveness of an antibiotic against a specific bacterium. C) The time it takes for an antibiotic to work is not described by the MIC. MIC is a measure of concentration, not time. D) The spectrum of bacteria the antibiotic targets is not defined by the MIC. The MIC value is specific to a particular antibiotic and bacterium, regardless of the spectrum of activity of the antibiotic.

5. Which property of a substance describes how much matter is packed into a given space?

A. Mass
B. Volume
C. Weight
D. Density

Correct answer: D

Rationale: Density is the property of a substance that describes how much matter is packed into a given space. It is calculated by dividing the mass of the substance by its volume. Mass refers to the amount of matter in an object, volume is the amount of space an object occupies, and weight is the force of gravity acting on an object's mass. Density specifically relates to how tightly packed the particles of a substance are.

6. Neon (Ne). Both He and Ne belong to Group 18 (Noble Gases) due to their complete and stable outer electron shells.

A. Electromagnetism
B. Gravity
C. Strong nuclear force
D. Weak nuclear force

Correct answer: C

Rationale: Strong nuclear force. This incredibly powerful force overcomes the repulsive electrostatic force between protons and binds the nucleus together.