What structure do mollusks use to excrete wastes?
a. gills
c. viscera
b. nephridia
d. foot

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.

The united states produces an average of 429 billion pounds of food annually. about 133 billion pounds of that food ends up as waste.the percentage of food that the united states wastes each year is %.

Why did the federal government end its support of yucca mountain as a site for long-term storage of nuclear water