C. The cell took in another ancient prokaryotic cell, which began living inside it.
If you are checking a cell for a zero value and the cell is blank, the test evaluates to true. For example, if you have the following formula in cell A1 =IF(B1=0,"zero","blank") and B1 is blank, the formula returns "zero" and not "blank" as expected.
If the range might contain a blank cell, you should use the ISBLANK function to test for a zero value, as in the following example: =IF(ISBLANK(B2),"blank",IF(B2=0,"zero","other")) Note that the above formula returns "zero" if there is a zero value in the cell, "blank" if the cell is blank, and "other" if anything else is in the cell.
You must always use the ISBLANK formula first before you test for a zero value. Otherwise you will always return a "true" for the zero value, and never get to the test for the ISBLANK formula.
The correct answer is "thoracic duct".
The thoracic duct (also called as the left lymphatic duct or the alimentary duct) is the structure wherein most of the lymph in the drained from the lymphatic vessels goes to this structure. In the thoracic duct, lymph flows up to the level of the brachiocephalic vein where lymph returns to the venous circulation.
Explanation:
Since lice feed on human blood, severe and chronic infestation can lead to blood loss and iron-deficiency anemia. 5 In addition, an allergic reaction to louse feces or bites may trigger a rash in some individuals.
