Answer:
An immune response is a reaction which occurs within an organism for the purpose of defending against foreign invaders. The first contact that an organism has with a particular antigen will result in the production of effector T and B cells which are activated cells that defend against the pathogen.
Explanation:
Its hard to believe it but its D.<span />
Answer: The European Union's most important water pollution act is called Water Framework Directive.
The demand for clean lakes and rivers, coastal beaches and groundwater by the environmental organizations and the citizens the commission made water conservation a chief priority under which the Water Framework Directive was made. The Water Framework Directive has some of key objectives like expansion of the scope of water protection for all types of water sources, water managements on the basins of rivers, ensuring proper quality standards, involvement of citizens and correct pricing etc.
