Given the task definition and input, reply with output. Given a scientific passage and an answer, generate a question for the given answer.

Passage: Antibodies These proteins recognize and combine with harmful materials, including both toxic chemicals and invasive microorganisms (such as bacteria and viruses). When an antibody binds to its target, it is tagged for destruction. This tag is recognized by white blood cells, which complete the process. Some antibodies also partially or completely deactivate their targets while waiting for further help from white blood cells. Answer: antibodies
Which proteins recognize and combine with harmful materials, including both toxic chemicals and invasive microorganisms?