According to the passage on antigen antibody immunity, one of the two important manifestations of antigen antibody immunity is lysis while the other is ____.

Introduction / Context:
This question is based on a scientific reading comprehension passage about antigen antibody immunity. Such passages often describe technical processes and mechanisms, and the questions check whether you can identify and recall key points rather than understand every specialised term.

Given Data / Assumptions:
- The passage explains how antibodies and antigens interact in the immune system. - It states that two important manifestations of antigen antibody immunity are lysis and another process. - Options given: lymphocytes, plasma, antigenic cells, phagocytosis. - We assume the question refers directly to wording in the passage.

Concept / Approach:
To answer, you should locate or recall the sentence in the passage that lists the two manifestations. The passage states that two important manifestations of antigen antibody immunity are lysis and phagocytosis. Therefore, the correct answer is phagocytosis. The other options name components or elements in the immune system but not the manifestation mentioned alongside lysis.

Step-by-Step Solution:
Step 1: Identify the relevant sentence in the passage. It says that two important manifestations of antigen antibody immunity are lysis and phagocytosis. Step 2: Note that lysis is already given in the question as one manifestation. Step 3: Recognise that the question asks for the other manifestation mentioned in that sentence. Step 4: Recall or re read that the second term listed is phagocytosis. Step 5: Compare with options and locate phagocytosis among them. Step 6: Confirm that lymphocytes, plasma, and antigenic cells are mentioned in the passage but not as the second manifestation alongside lysis. Step 7: Therefore, choose phagocytosis as the correct answer.

Verification / Alternative check:
A quick verification method is to understand the roles: lysis is described as rapid breaking of antigenic cells, whereas phagocytosis is described as the process in which antigenic particles are engulfed and often digested by specific cells. The passage explicitly groups these two as important manifestations of antigen antibody immunity. Lymphocytes are cells that produce antibodies, plasma is the liquid component of blood, and antigenic cells are targets, not manifestations themselves.

Why Other Options Are Wrong:
Lymphocytes in option A are a type of white blood cell that give rise to plasma cells and antibodies but are not named as a manifestation. Plasma in option B is the fluid part of blood and again is not presented as one of the two manifestations. Antigenic cells in option C are the cells that may be destroyed or engulfed, not the process itself.

Common Pitfalls:
In reading comprehension, students sometimes pick any familiar scientific term rather than the one explicitly mentioned in the relevant sentence. Another pitfall is misunderstanding the word manifestation, which here means observable effect or outcome, such as a process like lysis or phagocytosis. Always return to the exact wording of the passage and note whether a term refers to a process, a cell type, or a substance.

Final Answer:
The other important manifestation of antigen antibody immunity, besides lysis, is phagocytosis.