Answer:
Something that an antibody or T-lymphocyte binds to
Explanation:
As per the definition, antigens are the substances or molecules that are capable of inducing an immune response. When our immune system detects any unwanted substance or molecule in our body, the specific type of antibody is made against that antigenic substance and the antibody made against it binds to the antigen so that the other immune cells can recognize it and destroy it and protect us form its harmful effect. T-cell are also involved in recognizing antibodies and specific T-cell can bind to the antigen.
Biology is the study of living thing
Answer:
Due to environmental conditions.
Explanation:
With the passage of time, environmental conditions change which causes the evolution of of four legged land animals from fish like creature. This change occurs due to change in environment. In water, there is no need for legs because fish moves with the help of fins and tail but the organisms that lives on land has legs in order to move from one place to another so we can say that change in the physical structure of organism occurs due to environment.
