One characteristic of the immune response is specificity.
This means that immunity.

Choice A rationale

While the immune response originates in specific organs like the thymus, bone marrow, and lymph nodes, this statement describes the origin of immune cells and processes, not the fundamental characteristic of specificity, which relates to targeting particular antigens.

Choice B rationale

Similar to Choice A, the immune response involves specialized tissues throughout the body, such as lymphoid tissues. However, this describes the anatomical distribution of the immune system rather than the core principle of specificity in recognizing unique pathogens.

Choice C rationale

The immune response is indeed carried out by specific groups of cells, such as B lymphocytes and T lymphocytes, which have specialized functions. However, while these cells contribute to specificity, the most direct definition of specificity in immunity is the targeted response against a particular pathogen or antigen.

Choice D rationale

Specificity in immunity means that the immune system's response is highly targeted and precise. Each specific B and T lymphocyte is programmed to recognize and respond to a particular epitope (a specific molecular structure) on a pathogen, ensuring that the immune response is directed only against the invading microbe.

Choice E rationale

The immune response involves specialized tissues. However, this statement focuses on the location rather than the fundamental characteristic of specificity, which refers to the precise recognition and targeting of a particular pathogen or antigen by immune cells.

Choice D rationale

Hyposecretion, or inadequate hormone release, can indeed result from a combination of factors. Tumors or lesions directly destroying glandular tissue (primary hyposecretion), interference with the gland's ability to receive stimulating signals (secondary hyposecretion), or inadequate trophic hormone stimulation from a higher center all lead to insufficient hormone production.

Choice A rationale

Tumors or lesions that destroy an endocrine gland directly impair its ability to synthesize and secrete hormones, leading to primary hyposecretion. For example, damage to pancreatic islet cells can cause insufficient insulin production, leading to diabetes mellitus.

Choice B rationale

Tumors or lesions that interfere with a gland's ability to receive signals from another gland, such as the pituitary, result in secondary hyposecretion. If the adrenal cortex cannot respond to ACTH due to receptor damage, it will not produce sufficient corticosteroids.

Choice C rationale

Inadequate stimulation of the gland, such as insufficient release of a trophic hormone from the pituitary or hypothalamus, leads to insufficient hormone production. For example, if the pituitary does not release enough TSH, the thyroid gland will exhibit hyposecretion of thyroid hormones.