Which of the following are common features of expression vectors?
a. small segments of dna that encode tags for protein purification.
b. transcriptional start and stop sites
c. a tightly controlled promoter than can only be induced under certain circumstances
d. antibiotic resistance gene
e. all of the above are common features of expression vectors

there really is life in the deepest part

i was thinking 4.0 v hope this

answer >   yes we do, women; have three holes, urethral opening(pee hole, vagina, and the women pee/girls pee out of the urethra like the men do; only they have a single opening to pee/ejaculate.   (sorry if i'm too forward with this, but this is for a biology class, isn't it? )

hope that !         : )