Fill in the blanks:
$(1)$ In $+E$ effect,$\pi$ electrons from a multiple bond migrate to the ........... .
$(2)$ In $-E$ effect,$\pi$ electrons from a multiple bond migrate to the ........... .
$(3)$ ........... and ........... increase stability.
$(4)$ ........... inductive effect increases the acidic strength and ........... inductive effect decreases the strength of $-COOH$.

(D) $(1)$ The $\pi$ electrons migrate to the atom to which the attacking reagent gets attached.
$(2)$ The $\pi$ electrons migrate to the atom to which the attacking reagent does not get attached (i.e.,the other atom of the multiple bond).
$(3)$ Resonance and hyperconjugation increase stability.
$(4)$ $-I$ (negative inductive) effect increases the acidic strength,and $+I$ (positive inductive) effect decreases the acidic strength of $-COOH$.