Which of the following are part of the first line of defense against invaders: (select all that apply)

A. Chyle is a type of lymphatic fluid rich in fats absorbed from the intestines, but it is not the primary basis of all lymphatic fluid.
B. Secretions of lymph nodes contribute immune cells and filtering functions but do not form the main component of lymph.
C. Plasma is the correct answer. Lymphatic fluid originates from interstitial fluid, which in turn is derived from plasma that leaks out of capillaries. This fluid enters the lymphatic system and becomes lymph.
D. MALT (Mucosa-associated lymphoid tissue) is involved in immune responses in mucosal membranes but does not form the basis of lymphatic fluid.

A. Red blood cells are not typically found in lymph. Lymph is a clear fluid that circulates through the lymphatic system and normally does not contain red blood cells unless there is damage or leakage from blood vessels.
B. Proteins can be present in lymph, especially smaller ones that pass through capillary walls.
C. Water is a major component of lymph, making up the fluid part that helps transport cells and substances.
D. Lymphocytes are a key component of lymph, playing a central role in the immune response.