The lac operon in e. coli regulates genes that code for enzymes required for breakdown of lactose. the lac operon operon that is activated in the presence .

How does the carbon cycle involve an exchange of carbon

What is the main fuel source for the work of the cell

Ivan is looking at a cross section of a stem taken from a vascular plant. he sees two different types of vascular tissue: the xylem, which is closer to the center of the stem, and the phloem, located around the xylem, closer to the outside of the stem. how do these two structures work together in a living plant?