A man drops a baseball off of the top of the Empire State Building. If the action force is the Earth pulling on the ball, then what is the reaction force?
OA.
the acceleration of the ball
ОВ.
the ball pulling on the Earth
OC.
air resistance acting on the ball
OD
the ground pushing on the ball

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.