Answer:
Immune system of the body helps in fighting with the infectious agents that are foreign for the body. So the immune system protects us from infection.
When any foreign substance(antigen) comes in the body B-lymphocyte recognize it by binding the antigen through its receptor. After recognizing the antigen, B cell divides into antibody-producing plasma cell and memory cell.
Antibodies produced by plasma cells help in destroying the antigen by getting the antigen recognized by phagocytic cells or by complement activation.
B cells are antigen-presenting cell which present antigen to T cell and then T cell activates and produce chemicals that kill the antigen. Therefore the immune system has many immune cells that activate when an antigen comes in the body. This is how the immune system functions.
Answer:
6 in total; 3 viable and 3 non-viable
Explanation:
Robertsonian translocation is one of the types of structural alteration in chromosomes, in other words, a rearrangement between chromosomes, which can occur between five pairs of acrocentric chromosomes (chromosomes with the centromere close to the end of one of the "arms"): 13, 14, 15, 21 and 22.
An individual who has Robertson's translocation between chromosomes 14 and 21 generally has only 45 chromosomes.
In addition, a carrier of this type of translocation can theoretically produce 6 types of gametes, however 3 of them are not viable.
As for the three remaining gametes: One is normal, and among the other two, one is balanced and the last is unbalanced.
So, theoretically, when combining a normal gamete, the probability of a child with down syndrome being born through these conditions is 1/3 (considering that the probability of producing a certain type of gamete is equal for the three types).