Acell biologist examines a diploid cell from a particular species of butterfly during prometaphase of mitosis and determines that 10 centromeres are present. based on this finding, how many chromatids should be present in a single cell from this species in metaphase i of meiosis?

List the advantages and disadavantages of the switch from persistent chlorinated hydrocarbon pesticides (such as ddt) to nonpersistent organophosphate pesicides. have the benefits of the switch outweighed the disadvantages? explain.

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.

16. which of the following accurately describes a step within transcription? a. dna polymerase uses one strand of rna as a template to put together nucleotides. b. the dna strand is used as a template for which a complementary rna strand can be produced. c. the rna strand forms a template by which dna can be built. d. the rna strand is produced within the cytoplasm.