Fat globules and lymph combine to form a milky fluid called:

A. An antigen is any foreign substance (such as bacteria, viruses, or toxins) that triggers an immune response in the body. The immune system recognizes and responds to antigens, typically by producing antibodies.
B. Inflammation is a response of the body to injury or infection, characterized by redness, heat, swelling, and pain, but it is not a foreign substance itself.
C. An allergen is a specific type of antigen that causes an allergic reaction. While all allergens are antigens, not all antigens are allergens.
D. A lymphocyte is a type of white blood cell involved in the immune response, but it is not a foreign substance. Lymphocytes help recognize and respond to antigens.

A. T cells "mature" and become fully functional in the thymus – T cells are produced in the bone marrow, but they mature in the thymus. In the thymus, T cells undergo a selection process to become functional and capable of recognizing specific antigens.
B. T cells are produced by stem cells in bone marrow – T cells originate from stem cells in the bone marrow, where they first begin to develop. However, they mature in the thymus.
C. T cells are produced in the spleen – This is incorrect. While the spleen plays a role in immune responses, T cells are not produced there; they are produced in the bone marrow.
D. T cells "mature" and become fully functional in the tonsils – This is incorrect. Tonsils are part of the lymphatic system and play a role in immune defense, but T cells do not mature there; they mature in the thymus.