12. The process by which leukocytes squeeze through adjacent cells in a blood vessel wall is called __ . 1. leukocytosis 2. positive chemotaxis 3 emigration 4. cytoplasmic extending

## Step 1<br />The question is asking for the term that describes the process by which leukocytes, or white blood cells, squeeze through adjacent cells in a blood vessel wall. This process is a crucial part of the immune response, as it allows leukocytes to reach the site of infection or inflammation.<br /><br />## Step 2<br />Let's analyze each of the given options:<br /><br />1. Leukocytosis: This term refers to an increase in the number of white blood cells in the blood, usually in response to an infection or inflammation. It does not describe the process of leukocytes moving through the blood vessel wall.<br /><br />2. Positive chemotaxis: This term refers to the movement of cells towards a chemical stimulus. While leukocytes do move towards the site of infection or inflammation, this term does not describe the process of them moving through the blood vessel wall.<br /><br />3. Emigration: This term refers to the act of leaving one's place of residence or country to live elsewhere. In the context of biology, it refers to the movement of cells from one place to another. This term accurately describes the process of leukocytes moving through the blood vessel wall.<br /><br />4. Cytoplasmic extending: This term refers to the process of extending the cytoplasm of a cell. It does not describe the process of leukocytes moving through the blood vessel wall.