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 is the relationship between the Pauli exclusion principle and the structure of the atom?

A. It defines the maximum number of electrons allowed in each energy level.
B. It explains why oppositely charged particles attract each other.
C. It describes the wave-particle duality of electrons.
D. It determines the arrangement of protons and neutrons in the nucleus.

Correct answer: A

Rationale: It defines the maximum number of electrons allowed in each energy level. The Pauli exclusion principle states that no two electrons in an atom can occupy the same quantum state, which explains the specific sequence and structure of electron shells within the atom.

3. A birdbath has a hemispherical bowl with a diameter of 30cm. What is its volume?

A. 675 cu cm
B. 1350 cu cm
C. 2700 cu cm
D. 4050 cu cm

Correct answer: C

Rationale: Use half the formula for a sphere's volume: (2/3) * Ï€ * (radius)^3. Calculate the radius (15cm) and substitute: (2/3) * Ï€ * (15cm)^3 â‰ˆ 2700 cu cm.

4. A baseball is thrown into the air. At the peak of its trajectory, which of the following forces is acting on the ball?

A. Only gravitational force
B. Only the force of air resistance
C. Both gravitational force and the force of air resistance
D. Neither gravitational force nor the force of air resistance

Correct answer: A

Rationale: At the peak, the ball momentarily stops moving upwards. Its inertia keeps it moving horizontally, but there is no force propelling it upwards except for gravity pulling it down.

5. What is the outermost protective layer of the kidney?

A. Renal cortex
B. Renal medulla
C. Renal capsule
D. Renal pelvis

Correct answer: C

Rationale: The correct answer is C, renal capsule. The renal capsule is a tough fibrous layer that surrounds the kidney and provides protection. It helps maintain the shape of the kidney and serves as a barrier against infections and injuries. The renal cortex (A) is the outer region of the kidney where filtration occurs. The renal medulla (B) is the inner region of the kidney where urine is formed and collected. The renal pelvis (D) is a funnel-shaped structure that collects urine from the kidney and funnels it into the ureter. Therefore, the renal capsule is specifically the outermost protective layer of the kidney.