What do all elements in a column in the periodic table have in common?
their atoms have the same number of valence electrons.
their atoms have the same atomic mass.
their atoms have the same number of protons and electrons.
their atoms have the same number of neutrons.

Scientific method and data analysisa biology student wanted to determine if there is a relationship between resting heart rate and bodyheight. she gathered information from 12 classmates and constructed the table below.resting heart rate (beats per minute)student height (cm)155. 156156165180180190194195

Keeping in mind the life cycle of bacteriophages, consider the following problem: during the reproductive cycle of a temperate bacteriophage, the viral dna inserts into the bacterial chromosome where the resultant prophage behaves much like a trojan horse. it can remain quiescent, or it can become lytic and initiate a burst of progeny viruses. several operons maintain the prophage state by interacting with a repressor that keeps the lytic cycle in check. insults (ultraviolet light, for example) to the bacterial cell lead to a partial breakdown of the repressor, which in turn causes the production of enzymes involved in the lytic cycle. as stated in this simple form, would you consider this system of regulation to be operating under positive or negative control?

10. in which phase will crossing-over occur? a. mitosis b. metaphase ii c. prophase i d. meiosis ii