Some substances bout not others can cross the (blank) membrane of a cell

Which of these best describes an ionic bond?

Give the orbital configuration of the phosphorus (p) atom.

Diffraction is when light is bent around obstructions. which of the these observation about clouds would indicate diffraction? a) after rain storms, you can sometimes see rainbows. b) clouds are white or gray and cannot be seen through. c) on a cloudy day, the temperature tends to be cooler than a sunny day. d) the edges of dark clouds appear lighter. this