How many alleles are there for the four main types of human blood?

Three alleles.

Explanation:

Blood types are encoded thanks to three multiple alleles: IA, IB and i. Since we humans are diploids, these alleles can be combined into six different types: IAIA, IAi, IBIB, IBi, IAIB and ii. . Between alleles IA and IB, codominance occurs, ie both alleles express themselves. However, these alleles are dominant over allele i. We can represent this relationship as follows: IA = IB> i.

Human blood has four different phenotypes: type A, type B, type AB and type O, which form the well-known ABO system. The existence of these different blood types, discovered by the Austrian physician Karl Landsteiner (1868-1943) in the twentieth century, was central to the history of medicine as it allowed the development of transfusion techniques.

answer is b

  a   having low self-esteem

  b   having abusive family members

  c   having poor school attendance

  d   having friends who discuss gang life

living torture and being abused makes one not mind harming other people.

and also not being supported and abusing one turns one into this state.