Fill in the blanks -
these words may be used once, more than once or not at all: antivirals, antigens, antibodies, toxins, white blood cells

produce to destroy disease-causing microorganisms that enter the body. the disease-causing microorganisms have protein markers called on their surface which are detected by antibodies produced by the body and this the body recognise foreign material.

Waste water from industries and domestic sources can be treated by chlorination or ultraviolet radiation. there are pros and cons to using either chlorine or uv radiation to kill harmful microorganisms. what is one reason chlorination would be preferred over ultraviolet radiation? a) chlorine only eliminates visible impurities and is ineffective against microorganisms. b) chlorine not only kills bacteria but provides a residual effect on returning microorganisms. c) uv radiation can be used only to treat drinking water and is ineffective in treating waste water. d) ultraviolet radiation is more effective