1. Certain medications can suppress the immune system to treat autoimmune diseases or prevent organ rejection after transplants. What is a potential risk associated with immunosuppressive drugs?

A. Increased risk of developing allergies
B. Increased susceptibility to infections
C. Both a and b
D. Neither a nor b

Correct answer: C

Rationale: The correct answer is C: 'Both a and b.' Immunocompromised individuals, who take immunosuppressive drugs, are at an increased risk of developing allergies due to the altered immune response. Additionally, these drugs suppress the immune system's ability to fight off infections, making individuals more susceptible to various pathogens. Therefore, both increased risk of developing allergies and increased susceptibility to infections are potential risks associated with immunosuppressive drugs, making option C the correct choice.

2. The urethra is the tube that carries urine from the bladder to the outside of the body. How does urine flow through the urethra?

A. Continuously
B. Only when the bladder is completely full
C. Under voluntary control of sphincter muscles
D. A combination of b) and c)

Correct answer: C

Rationale: The correct answer is C: "Under voluntary control of sphincter muscles." The urethra is the tube responsible for carrying urine from the bladder to the outside of the body. Urine flow through the urethra is not continuous but rather under voluntary control. The sphincter muscles, located at the opening of the bladder and urethra, help control the release of urine. This control allows individuals to regulate when and where they empty their bladder, providing a mechanism to prevent involuntary leakage of urine. Therefore, option C accurately describes how urine flows through the urethra.

3. What is the shape of the DNA molecule?

A. Linear
B. Circular
C. Double helix
D. Straight chain

Correct answer: C

Rationale: Rationale: The shape of the DNA molecule is a double helix. This structure was first described by James Watson and Francis Crick in 1953. The double helix shape consists of two strands that are twisted around each other in a spiral. This shape allows DNA to be compactly stored within the cell nucleus and provides stability to the molecule. The other options (A) Linear, (B) Circular, and (D) Straight chain do not accurately describe the shape of the DNA molecule.

4. Which of the following is a property of amphiprotic substances?

A. React with acids only
B. React with bases only
C. Can act as both acids and bases
D. Are inert in chemical reactions

Correct answer: C

Rationale: Amphiprotic substances can donate or accept a proton, so they can act as both acids and bases. The other choices do not accurately describe amphiprotic substances.

5. What is the name of the white blood cells that attack foreign invaders?

A. Phagocytes
B. Lymphocytes
C. Platelets
D. Red blood cells

Correct answer: A

Rationale: Rationale: Phagocytes are a type of white blood cell that plays a crucial role in the immune system by engulfing and digesting foreign invaders such as bacteria, viruses, and other harmful substances. They are part of the body's innate immune response and are essential for protecting the body against infections. Lymphocytes, on the other hand, are another type of white blood cell involved in the adaptive immune response, producing antibodies and coordinating immune responses. Platelets are cell fragments involved in blood clotting, while red blood cells are responsible for carrying oxygen to tissues.

6. 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) * Ãâ‚¬ * (radius)^3. Calculate the radius (15cm) and substitute: (2/3) * Ãâ‚¬ * (15cm)^3 Ã¢â€°Ë† 2700 cu cm.