Answer: (A) Distilled Water
<span>The vascular tissues in plants are composed of Xylem and Phloem.These tissues allow nutrients and water to be transported in theother parts of the plant.</span>
The correct answer is (c) discover antigens in body fluids.
B lymphocytes act as antigen presenting cells that recognizes and displays the antigen to the white blood cells. These cells process the antigens that are present in body fluids. Professional antigen presenting cells includes B-lymphocytes, macrophages, dendritic cells, etc.
Answer is: a secretary smokes a cigarette in a crowded break room.
External cost Is when consuming a good or servise imposes a cost to a third party. In this case, smoking affects other people in break room, causing pollution and health related problems.