Select the correct answer from each drop-down menu.
Jeremy is writing an article for his school magazine about the lymphatic and immune system. Choose the most appropriate words to complete the sentences.
Lymphatic and Immune system
are tiny organisms not visible to the naked eye and include bacteria, viruses, and protozoans.
are blood cells that protect the body from disease. They circulate in the lymphatic vessels and reside in lymphatic organs.
The two main types of leukocytes are lymphocytes and
, which effectively eat up bacteria and diseased cells.