The food web below shows some of the feeding relationships among organisms in Arctic waters. A change in the population of one organism can affect the entire food web. Based on the information in the food web, which organism would be least affected by overfishing for cod in Arctic waters? * seals
shrimp
baleen whales
toothed whales

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.

Which of the organisms listed below performs nitrogen fixation? a. legumes b. plants c. bacteria d. fungi

There are only about 250,000 known fossil species. true or false