The correct option is A, FEEDING HABIT AND MIGRATION. From the passage given above, it can be seen that seagulls are scavengers, they usually eat from garbage dumps while wild geese eat seeds and insects, thus they differ in feeding habit. In term of migration, seagulls does not follow seasonal pattern of annual migration while wild geese do. These are the contrasts between the two birds.
The correct answer is antigens and epitope.
An antigen is a substance which triggers an immune response in an organism. This can be either a foreign substance, such as a pathogen, or a specific part of the host organism (in this case this is an autoimmune response). The presence of an antigen activates a specific part of the immune system, called antibody. Each antigen has a specific antibody, which is tailored by the immune system accordingly. More specifically, the antibody has a specific structure, called paratope, which is complementary and binds like a key to a specific structure of the antigen, called epitope.
M+90=150
minus 90 in both sides
m=60
