Answer:
antigen-MHC protein complexes
Explanation:
Helper T-cells recognise antigens that are complexed with MHC proteins and interact with target cells. Antibodies can be produced against a single antigen in a variety of ways. Toxic shock syndrome is a relatively mild condition that resembles other minor allergy responses. Antigen-presenting cells break down superantigens.
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Population decreases by 15.
Birth rate means more population (positive), death rate means less population (negative), immigration means more (positive), and emigration means less (negative). So, just add and subtract the appropriate numbers:

Negative 15 people means that the population decreases by 15.
Answer:
Four characteristics used to describe population would be geographic range, density and distribution, growth rate, and age structure
Explanation:
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