Science, Maths & Technology
What is a virus?
...adaptive, both of which provide protection from viral infection. The innate immune system comprises physical barriers (e.g., mucous), chemical messengers (e.g., cytokines; a type of signalling molecule used by cells) and various types of cells (e.g., leukocytes; white blood cells) and is the first line of defence against invading microorganisms. A particularly important...