Please help!
1. In this model of a molecule of ammonia, NH3, how many covalent bonds are represented?

A. 1 covalent bond
B. 2 covalent bonds
C. 3 covalent bonds
D. 4 covalent bonds

Suppose you have three polarizing filters, with the second at an angle of 42∘ to the first and the third at an angle of 90∘ to the first. by what perfect will the original intensity of unpolarized light be reduced to after passing through all three filters?

Complete the statement about memory improvement. ( )involves organizing and breaking down information into easier groups to expand capacity. rehearsal is the verbal repetition of information. these techniques are especially important for the improvement of ( ) memory.

(1 point) match the differential equations and their vector valued function solutions. you may wish to multiply at least one solution out fully, to make sure that you know how to do it. you can get the other answers quickly by process of elimination and just multiply out one row element.