sulfur has three common isotopes. one of the isotopes of sulfur has 18 neutrons. it’s atomic number is 16. which symbol correctly identifies this isotope of sulfur? why

compost can be added to topsoil as a:

pesticide

name and explain one of the event that occurs during meiosis that increases the variation in offspring even more than simple reproduction?

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.