Final answer:
The word 'affinity' generally means a fondness or natural liking for something. In the context of immunology, it refers to the strength of the binding between an antibody and antigen. 'Fondness' is the most appropriate choice among the given options.
Step-by-step explanation:
The word 'affinity' has multiple definitions depending on the context in which it is used. In general, affinity means a natural liking or sympathy for someone or something, or a similarity of characteristics suggesting a relationship, especially a resemblance in structure between animals, plants, or languages. Thus, among the provided options, the meanings closest to 'affinity' are '1) partiality' and '2) fondness'.
In a biological or immunological context, affinity refers to the strength of a single antibody-antigen interaction. The term describes how tightly an antibody binds to its specific antigen. A higher affinity indicates a stronger and more stable bond. This level of detail is important in understanding immune responses and in designing treatments and vaccines that target specific pathogens.
However, if we have to choose one correct meaning of 'affinity' from the provided options, '2) fondness' would be the most accurate, as it reflects a sense of preference or positive feeling toward something, whereas 'partiality' can sometimes imply an unfair bias.