Which of the following statements about antibodies is correct?
a. antibodies are polypeptides.
b. antibodies are produced by the bone marrow.
c. antibodies are pathogenic foreign substances.
d. antibodies kill bacteria but not viruses.

Which statement correctly compares metaphase i and metaphase ii? in metaphase ii twice as many chromosomes line up along the middle of the cell as in metaphase i. in metaphase i twice as many chromosomes line up along the middle of the cell as in metaphase ii. in metaphase ii twice as many chromosomes are pulled to opposite ends of the cell as in metaphase i. in metaphase i twice as many chromosomes are pulled to opposite ends of the cell as in metaphase ii.