Trong 1ml dung dịch HX a mol/l có 5,4×10¹⁹ phân tử HX; 6×10¹⁸ ion X⁻. Tính a

Why does the sun appear to be the brightest star in the sky? a- its apparent brightness is much greater than other stars. b- it burns more gas, making it brighter than any other star. c- it is the largest star in the galaxy, so it is the brightest star. d- its relative distance to earth is closer than the other stars.

Mary is conducting an experiment on how pollution affects plant growth. how can she ensure that her data are reliable?

The three types is stress that act on earths rocks are compression, tension, and