The diameter of the nucleus of an atom is about 10-12 centimeters. What is this diameter in standard form?
A) -0.00000000001 cm
B) 0.000000000100 cm
C) 0.000000000001 cm
D) 0.000000001000 cm

If the angle bisectors of a pair of opposite angles of a quadrilateral are the opposite sides of a parallelogram formed by the two angle bisectors and two sides of the quadrilateral, is the quadrilateral always a parallelogram? explain your answer.