Often, a goby fish and a shrimp will live together in a burrow the shrimp has dug in the sand. The shrimp is almost blind and therefore is unable to see predators approaching when he is outside of the burrow. When the shrimp is in danger, the goby fish touches the shrimp with its tail to warn him. Then, both go back into their burrow for safety.

19. scientists use meteorites that hit earth to provide evidence of the composition of earth's interior because they hypothesize that

Legumes, a type of plant, require rhizobia, a type of soil bacteria, to survive since these organisms fix nitrogen during photosynthesis. rhizobia use the legumes for food. what would most likely happen to the legume population if rhizobia suddenly became extinct?

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.