What type of immunity does a fetus gain when antibodies are received from the mother via the placenta?

Rationale:

A. Apples are generally considered low-allergen foods. While some individuals may have oral allergy syndrome related to pollen-food cross-reactivity, apples are not among the most common food allergens.

B. Shrimp is a shellfish, which is one of the major common food allergens. Shellfish allergy can trigger severe allergic reactions, including urticaria, angioedema, gastrointestinal symptoms, or anaphylaxis. Shellfish allergies are lifelong in most cases and are more common in adults than children.

C. Chicken is rarely a cause of food allergy. Most individuals can tolerate cooked chicken without immune reactions. It is not listed among common allergens.

D. Rice is generally considered hypoallergenic and is rarely associated with allergic reactions. It is often recommended as a safe food for infants or people with food sensitivities.

Rationale:

A. Sickle cell anemia is a monogenic disorder caused by a mutation in the HBB gene, which leads to abnormal hemoglobin S production. It follows a Mendelian autosomal recessive inheritance pattern, meaning a person must inherit two defective alleles (one from each parent) to express the disease. Environmental factors have little influence on whether the disease occurs, although they can affect disease severity.

B. Cystic fibrosis is caused by mutations in the CFTR gene and is also a single-gene autosomal recessive disorder. Disease expression is largely determined by genetics, although certain environmental factors, like respiratory infections, may influence symptoms and progression. It is not considered multifactorial because a single gene mutation is sufficient to cause the disorder.

C. Hemophilia A is an X-linked recessive disorder caused by a mutation in the factor VIII gene. Males are predominantly affected because they have only one X chromosome. This disorder follows a single-gene inheritance pattern, and while environmental factors can influence bleeding risk, the underlying cause is genetic alone.

D. Cleft palate is a classic example of a multifactorial disorder. It results from the interaction of multiple genes and environmental factors. Genetic predisposition may increase risk, but environmental influences—such as maternal smoking, alcohol use, certain medications, or nutritional deficiencies during pregnancy—can trigger or exacerbate the condition. Unlike single-gene disorders, multifactorial conditions do not follow simple Mendelian inheritance and often appear sporadically within families, though they may recur more frequently among relatives.