Astudent sets up a compost bin outdoors. inside the bin microorganisms convert the student’s vegetable and paper scraps into rich fertilizer. which of the following best describes the role that these microorganisms play in natural habitats? a the microorganisms balance the numbers of producers and consumers. b the microorganisms keep nutrients cycling through the ecosystem. c the microorganisms turn solar energy into sugars. d the microorganisms function as autotrophs.

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.

Restriction enzymes are used in making recombinant dna. describe the role restriction enzymes perform when constructing recombinant dna.

Crossing over and independent assortment are important activities that occur during meiosis. what is the significance of these activities