1. Fingernails and toenails are made primarily of:

A. Collagen (Collagen is found in the dermis)
B. Keratin
C. Melanin (Melanin provides pigment, not structure)
D. Sebum (Sebum is an oily substance)

Correct answer: B

Rationale: The correct answer is B: Keratin. Fingernails and toenails are primarily made of a tough protein called keratin. Keratin is a fibrous structural protein that also makes up hair and the outer layer of skin. Collagen, as mentioned in option A, is found in the dermis of the skin and is responsible for providing strength and elasticity to the skin. Melanin, as in option C, is a pigment that gives color to the skin, hair, and eyes, but it does not contribute to the structure of nails. Sebum, as in option D, is an oily substance produced by the sebaceous glands in the skin to moisturize and protect the skin, but it is not a component of nails.

2. What does "monophyletic" mean in the context of classification?

A. A group with a single representative organism
B. A group with diverse and unrelated members
C. A group with similar functions but different origins
D. A group descended from a common ancestor

Correct answer: D

Rationale: Rationale: In the context of classification, "monophyletic" refers to a group that includes a common ancestor and all of its descendants. This group shares a single evolutionary origin and forms a complete branch on a phylogenetic tree. Monophyletic groups are considered natural and valid taxonomic units because they reflect evolutionary relationships accurately. Option D is the correct choice as it accurately defines the term "monophyletic" in the context of classification.

3. What is the characteristic property of acids?

A. Bitter taste
B. Sour taste
C. Slippery feel
D. Sweet taste

Correct answer: b

Rationale: Acids typically have a sour taste. The other choices do not accurately describe the characteristic properties of acids.

4. What is the name of the curved bone in the back that provides support and attachment for muscles?

A. Sternum
B. Scapula
C. Clavicle
D. Vertebral column

Correct answer: D

Rationale: The correct answer is D: Vertebral column. The vertebral column, also known as the spine or backbone, is a series of small bones called vertebrae that provide support and protection for the spinal cord. It also serves as an attachment point for various muscles in the back. The sternum, scapula, and clavicle are all bones in the upper body, but they do not specifically provide support and attachment for muscles in the back like the vertebral column does.

5. Which vitamin is known to play a vital role in immune function?

A. Vitamin A
B. Vitamin B12
C. Vitamin D
D. Vitamin E

Correct answer: D

Rationale: The correct answer is Vitamin D. Vitamin D is known to play a vital role in immune function as it helps regulate the immune system's response to infections and reduces inflammation. It is involved in the production of antimicrobial peptides that help fight off pathogens. Vitamin A is important for vision and skin health, Vitamin B12 is essential for red blood cell formation and neurological function, and Vitamin E is an antioxidant that protects cells from damage. However, Vitamin D specifically stands out for its crucial role in supporting the immune system, making it the correct answer in this context.

6. Which part of the respiratory system is responsible for gas exchange between the blood and inhaled air?

A. Trachea
B. Larynx
C. Alveoli
D. Pharynx

Correct answer: C

Rationale: The correct answer is C, 'Alveoli.' The alveoli are tiny air sacs located at the end of the bronchioles in the lungs where gas exchange occurs. Oxygen from the inhaled air diffuses through the thin walls of the alveoli and into the bloodstream, while carbon dioxide from the blood diffuses into the alveoli to be exhaled. The trachea (A) is the windpipe that carries air to and from the lungs; the larynx (B) contains the vocal cords and helps with swallowing; and the pharynx (D) is the part of the throat that connects the mouth and nasal cavity to the esophagus and trachea, but it is not directly involved in gas exchange.