1. The innate immune system provides:

A. Nonspecific, immediate defense against pathogens
B. Specific, long-term immune response through memory cells
C. Both (a) and (b)
D. Neither (a) nor (b)

Correct answer: A

Rationale: The correct answer is A: 'Nonspecific, immediate defense against pathogens.' The innate immune system is the body's first line of defense against pathogens and provides a rapid, nonspecific response. It includes physical barriers like the skin, chemical barriers like stomach acid, and cellular responses like inflammation. This system does not involve memory cells or provide long-term immunity, which are characteristics of the adaptive immune system. Therefore, option A accurately describes the function of the innate immune system as a quick and nonspecific defense mechanism.

2. You need to repaint a cylindrical water tank with a diameter of 2 meters and a height of 3 meters. Assuming one can of paint covers 10 sq m, how many cans do you need (consider only the exterior surface)?

A. 6 cans
B. 9 cans
C. 12 cans
D. 15 cans

Correct answer: C

Rationale: Calculate the surface area of the cylinder and divide by the coverage area per can.

3. Half-life refers to the characteristic time it takes for:

A. Radioactive intensity to completely disappear
B. The number of neutrons in a nucleus to double
C. The number of protons in a nucleus to change
D. An isotope to decay by half of its initial quantity

Correct answer: D

Rationale: The correct answer is D: An isotope to decay by half of its initial quantity. The half-life of a substance is the time it takes for half of the initial quantity of radioactive atoms to decay. This is a characteristic property of each radioactive isotope and is used to determine the rate of decay of a substance. Option A is incorrect because radioactive intensity does not completely disappear in half-life, it only decreases by half. Options B and C are unrelated to the concept of half-life and do not accurately describe its definition.

4. Which of the following is an example of a nosocomial infection?

A. The common cold contracted from a family member
B. A urinary tract infection (UTI) acquired during a catheterization
C. A fungal skin infection from contaminated soil
D. Food poisoning from undercooked chicken

Correct answer: B

Rationale: Rationale: A nosocomial infection, also known as a healthcare-associated infection (HAI), is an infection that is acquired in a healthcare setting. In this case, a UTI acquired during a catheterization procedure is a classic example of a nosocomial infection. Catheterization involves the insertion of a tube into the urinary tract, which can introduce bacteria into the urinary system and lead to an infection. Nosocomial infections are a significant concern in healthcare settings due to the potential for increased morbidity, mortality, and healthcare costs. Let's review the other options: A) The common cold contracted from a family member - This is not a nosocomial infection as it is acquired outside of a healthcare setting. C) A fungal skin infection from contaminated soil - This is not a nosocomial infection as it is acquired from environmental exposure, not in a healthcare setting.

5. Which type of symbiosis is where both organisms benefit from the interaction?

A. Mutualism
B. Commensalism
C. Parasitism
D. Predation

Correct answer: A

Rationale: Rationale: Mutualism is a type of symbiosis in which both organisms involved benefit from the interaction. This relationship is characterized by cooperation and mutual support, leading to advantages for both parties. In mutualistic relationships, each organism provides something that the other needs, resulting in a mutually beneficial outcome. Examples of mutualism include the relationship between bees and flowers (pollination) and the partnership between nitrogen-fixing bacteria and leguminous plants.

6. A ball is thrown horizontally off a cliff. Which of the following forces is responsible for its downward motion?

A. The force of throwing
B. Normal force from the air
C. Tension force from the string (if used)
D. Gravitational force

Correct answer: D

Rationale: The gravitational force is responsible for the downward motion of the ball. When the ball is thrown horizontally off a cliff, the only force acting on it in the vertical direction is the force of gravity, which pulls the ball downward towards the ground. The other forces mentioned (force of throwing, normal force from the air, tension force from the string) do not contribute to the ball's downward motion in this scenario.