4x4 block to cross between FfNN and FFNn

What kind of bond is created by the attraction between atomic particles of opposite charge? ionic bond hydrogen bond covalent bond nuclear bond

Imagine a self-reactive t cell that has not undergone clonal deletion in the thymus (that is to say, it has escaped central tolerance). if it encounters self antigen in the absence of an infection or inflammation, what will happen to this self-reactive t cell? (select two answers) (a) the t cell undergoes clonal expansion. (b) the t cell gains effector functions. (c) the t cell undergoes apoptosis. (d) the t cell becomes activated. (e) the t cell becomes anergic.

Which atmospheric later is where earths northern and southern lights occur