Which condition would most likely result in a human body being unable to defend itself against pathogens and cancerous cells?

Correct Answer: D

Rationale: The correct answer is D because the human immunodeficiency virus (HIV) attacks and weakens the immune system, making the body unable to defend itself against pathogens and cancerous cells. HIV specifically targets CD4 T cells, crucial for coordinating immune responses. This leads to a compromised immune system, leaving the body vulnerable to infections and unable to combat cancerous cells effectively. Choice A is incorrect as a genetic tendency toward diabetes does not directly impact the body's ability to defend against pathogens and cancerous cells. Choice B is incorrect as ringworm is a fungal infection that can be treated and does not typically affect the immune system in a way that compromises defense mechanisms. Choice C is incorrect as the production of antibodies in response to an infection is a normal immune response that helps the body fight off pathogens, rather than weakening the immune system.

Correct Answer: B

Rationale: The correct answer is B: Rheumatoid factor. An increase in rheumatoid factor can indicate arthritis, specifically rheumatoid arthritis, as it is an autoantibody that targets healthy tissue in the joints. This is a key diagnostic marker for rheumatoid arthritis. A: Direct Coomb's test is used to detect antibodies on the surface of red blood cells, not specific to arthritis. C: Blood urea nitrogen (BUN) is a measure of kidney function and not typically associated with arthritis. D: Platelet count is unrelated to arthritis and is more indicative of clotting disorders or other conditions.

Correct Answer: C

Rationale: The correct answer is C: Acquired immunity develops after birth. This statement is correct because acquired immunity refers to the immunity that develops after exposure to antigens, such as through infection or vaccination. It involves the immune system recognizing and remembering specific pathogens to provide protection in the future. This shows the mother understands the difference between natural (innate) immunity, which is present at birth, and acquired immunity, which develops over time. Incorrect choices: A: Natural immunity develops when my baby receives immunizations - This is incorrect as immunizations are a form of acquired immunity. B: Natural immunity is only present before the baby is born - This is incorrect as natural immunity is present at birth and acquired immunity develops after birth. D: Acquired immunity develops only after exposure to an illness - This is incorrect as acquired immunity can also develop through vaccinations, not just exposure to illnesses.

Correct Answer: D

Rationale: Iron is primarily absorbed in the duodenum, the first part of the small intestine. The duodenum is where iron is released from food and converted into a form that can be absorbed by the body. The acidic environment in the stomach helps to break down iron-containing compounds, but actual absorption occurs in the duodenum. The ileum and jejunum are also parts of the small intestine, but they are not the primary sites of iron absorption. The stomach is involved in initial digestion but not in the absorption of iron. Therefore, the correct answer is D, the duodenum.

Correct Answer: B

Rationale: World AIDS Day is celebrated on December 1st globally to raise awareness about HIV/AIDS. This date was chosen to honor those who have died from the illness and support those living with it. Option A, May 12th, Option C, July 4th, and Option D, April 1st, are incorrect as they do not correspond to the designated date for World AIDS Day.