Another difference is that protists<span> belong to the kingdom </span>Protista<span>, while </span>bacteria<span> are members of the Monera kingdom. </span>Bacteria<span> are uni-cellular organisms that do </span>not<span> contain organelles like a nucleus or chloroplasts.
if this helps </span>
Macrophages engulf foreign material and destroy them using lysozymes.
When presented with antigen by antigen presenting cells, Helper –T cells produce
cytokines that activate B cells and triggers the adaptive immune response. T-helper cells determine the specificity of the adaptive response to an antigen. Cytotoxic-T-cells
destroys infected cells that have displayed an antigen on the MHC I surface receptors.
Suppressor T cells enable negative feedback by downregulating
immunity in cases when a foreign antigen
is eliminated. It also prevents autoimmunity.
Plasma cells are repsosncible for the production of antibodies in the humoral
immune response. Memory B and T cells ensure the immunity can remember an
infectious agent and therefore can launch a faster response in case of re-infection.
The answer would be A. Because orifice means opening. So it would be " The orifice of the octopus is at its center, where its arms meet. Hope that helps!!