Why is it necessary for meiosis to produce cells with fewer chromosomes

Ahypothesis that has been tested again and again , with similar results each time may become a law , true or false

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?

Which substance contains thylakoids? a) nadph b)atp c)stroma d)chloroplast