**Core Concept**
The question tests the understanding of immunology, specifically the similarities and differences between T cells and B cells, which are crucial components of the adaptive immune system. T cells and B cells are lymphocytes that play key roles in cell-mediated and humoral immunity, respectively.

**Why the Correct Answer is Right**
Since the correct answer is not provided, let's discuss a key difference: T cells require antigen presentation via MHC molecules to become activated, whereas B cells can recognize antigens directly without MHC presentation. This fundamental difference in antigen recognition mechanisms underlies many distinctions in their functions and behaviors.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific details of option A, we cannot directly address why it's incorrect, but typically, options might include aspects like antigen recognition, cell surface markers, or cytokine production, many of which do have similarities or differences between T and B cells.
**Option B:** Similarly, without specifics, option B could potentially be incorrect due to overlooking the nuances in T and B cell biology, such as their development, activation requirements, or effector functions.
**Option C:** This option might be addressing a specific feature that is indeed shared or not shared, but without details, it's challenging to provide a precise explanation.
**Option D:** Assuming this is the correct answer due to the lack of provided information, the explanation would hinge on identifying a unique characteristic of one cell type not present in the other.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that while both T and B cells are essential for immune responses, their mechanisms of action and the contexts in which they are most effective differ significantly. Understanding these differences is crucial for diagnosing and treating immune-related disorders.

**Correct Answer:** Correct Answer: D. Phagocytosis is a feature not shared between T cells and B cells, as B cells can perform phagocytosis but it's not their primary function, and T cells do not phagocytose.