Which of the following is true regarding clonal selection theory?Cassidy RhodyID: 112703Question 69Select one:Monocytes are constantly sampling the environment for antigensLymphocytes are constantly sampling the environment for antigensCells that recognize and bind strongly to self cells are positively selectedCells that recognize and bind to non-self antigens are positively selected

The statement that is true regarding clonal selection theory is: "Cells that recognize and bind to non-self antigens are positively selected".

Here's why:

The clonal selection theory is a scientific theory in immunology that explains the functions of cells (lymphocytes) of the immune system in response to specific antigens invading the body. According to this theory, when a foreign antigen enters the body, only the pre-existing lymphocytes that can recognize and bind to the antigen are selected and activated. These selected cells then proliferate and differentiate into a clone of effector cells and memory cells.

So, the cells that recognize and bind to non-self antigens (foreign substances) are positively selected, not the cells that bind strongly to self cells. The immune system typically does not attack the body's own cells (self cells), and cells that do are usually eliminated through a process called negative selection.

Monocytes and lymphocytes do play a role in the immune response, but they are not "constantly sampling the environment for antigens" as suggested in the other options. Monocytes are a type of white blood cell that can differentiate into macrophages and dendritic cells to respond to infections. Lymphocytes, which include B cells and T cells, are responsible for the adaptive immune response. However, it's not accurate to say they are constantly sampling the environment for antigens.