Following the sequence of Mendel's heritability study, which of the following is true? A
Mendel began by breeding two of the same true-breeding parents.
B
Mendel began by breeding two different types of true-breeding parents.
C
The offspring of the P generation were known as the first filial generation.
D
Both B and C.

clinically, some people often have repeated allergies, eczema and respiratory infections or other parts of the infection, in this case, in addition to some routine tests such as tests for white blood cells, immunoglobulin series, lymphocyte subsets, etc., the five immune immunoglobulin tests are also necessary.

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explanation: