What group of plants was found in the mesozoic but not in the paleozoic?

What is true for a substance that releases energy

Take a look at this dandelion. the yellow flower on the right is pollinated and the seeds on the left are transported by

You wish to prepare a buffer consisting of acetic acid and sodium acetate with a total acetic acetate plus acetate concentration of 250 mm and a ph of 5. what concentrations of acetic acid and sodium acetate should you use