Lymphocytes: a. possess mhc antigens for recognizing self. b. have membrane receptors that recognize foreign antigens. c. gain tolerance to self by destruction of lymphocytes that could react against self. d. develop into clones of b and t cells with extreme variations of specificity. e. all of the choices are correct.

The correct answer is e. all of the choices are correct.

Explanation:

A lymphocyte is a type of white blood cell and fulfills several functions in the immune system.  

a. Lymphocytes possess MHC antigens for recognizing self.

The major histocompatibility complex (MHC) is a region of very polymorphic genes whose products are expressed on the surface of almost all body cells. The molecules produced by these genes have the function of regulating the response of the immune system, especially the response mediated by T cells. The MHC of each individual influences the repertoire of epitopes that can recognize their T lymphocytes. Therefore, the capacity response to pathogens, they depend partially on that specific endowment of alleles of the MHC complex.

b. Lymphocytes have membrane receptors that recognize foreign antigens.

There are 2 types of lymphocytes, T lymphocytes and B lymphocytes, which mature from common lymphoid precursors present in the bone marrow. Each lymphocyte expresses a unique type of receptor that specifically recognizes an antigen, which is known as clonotypic receptors. T lymphocyte antigen (TCR) receptors recognize peptide antigens, presented by the major histocompatibility complex membrane molecules of antigen presenting cells1, while B lymphocyte antigen (BCR) receptors recognize soluble antigens .

c. Lymphocytes gain tolerance to self by destruction of lymphocytes that could react against self.

Tolerance is a phenomenon of great complexity and like any immune response, it is specific, transient and lies in the elimination or destruction of T and B lymphocytes, which are reactive to themselves during development.

d. Lymphocytes develop into clones of B and T cells with extreme variations of specificity.

Lymphocytes destined to be B lymphocytes enter regions not yet identified in the bone marrow, while lymphocytes destined to be T lymphocytes migrate to the thymus cortex. Once they become immune competent, they leave their respective maturation sites, enter the lymphoid system and undergo mitosis, and form a group of identical cells known as clones. All members of a particular clone can recognize and respond to the same antigen. The clone secretes clonotypic antibodies, identical to each other, and different from those of other clones.

answer: tributaries flow into rivers.

wetland is a biome that develops when the water gets accumulated in a land exhibiting a huge depression. these form either seasonally or permanently. the water in the wetland comes from rivers, lakes, ocean, flood, rain or other sources. the wetlands includes mangroves, marshes and peatland.

tributaries flow into the rivers develops a wetland because such water will get deposited in the depression and will restrict the original flow of tributary water. hence, water with low drainage current combines with the river water.

common management practices in dairy and poultry farming are: (i) proper shelter facilities and their regular cleaning. (ii) some basic hygienic conditions such as clean water, nutritious food, etc. (iii) animals are kept in spacious, airy, and ventilated place.